Google スプレッドシートには、SUM や AVERAGE などの組み込み関数が多数用意されており、Google スプレッドシートのセル内から呼び出すことができます。スプレッドシート アドオンでは、これらの組み込み関数を補完する追加のカスタム関数を定義できます。ユーザーがアドオンをインストールすると、アドオンに含まれる定義済みのカスタム関数がすぐに使用可能になります。アドオンは、カスタム関数定義のみで構成することもできます。カスタム関数定義は、主に定義を含むアドオンを公開することで他のユーザーと共有されます。
アドオンのカスタム関数を作成する
アドオン スクリプト プロジェクトで定義された関数は、カスタム関数として使用できます。関数を実装してアドオンをインストールすると、他の組み込みの Google スプレッドシート関数と同じようにカスタム関数を呼び出すことができます。スプレッドシートのセルに = を入力し、その後に関数名と必要なパラメータを入力します。エラーがなければ、関数から返された結果がシートのセルに配置され、必要に応じて隣接するセルにオーバーフローします。
[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["必要な情報がない","missingTheInformationINeed","thumb-down"],["複雑すぎる / 手順が多すぎる","tooComplicatedTooManySteps","thumb-down"],["最新ではない","outOfDate","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["サンプル / コードに問題がある","samplesCodeIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-07-31 UTC。"],[[["\u003cp\u003eGoogle Sheets add-ons enhance spreadsheets with custom workflows, external system connections, and integration with other Google Workspace apps.\u003c/p\u003e\n"],["\u003cp\u003eAdd-ons, built using Apps Script, enable data manipulation, custom menus, dialogs, and functions, triggered by specific events.\u003c/p\u003e\n"],["\u003cp\u003eCustom functions extend Google Sheets' built-in formulas, accessible directly within cells, but require adherence to naming and usage guidelines.\u003c/p\u003e\n"],["\u003cp\u003eGoogle Sheet add-ons provide extended functionality but cannot currently distribute or utilize pre-recorded macros.\u003c/p\u003e\n"]]],["Google Sheets add-ons, built with Apps Script, extend functionality by allowing users to read, edit, visualize, and format data. They can access the Google Sheets API, create custom menus, dialogs, sidebars, and custom functions. Add-ons can also use triggers to run functions on specific events. Custom functions, when created within an add-on, become immediately available to users after installation, following specific naming and usage guidelines. Macros, while recordable actions in Sheets, are not distributable with add-ons.\n"],null,["# Extending Google Sheets with add-ons\n\n[Google Sheets](https://workspace.google.com/products/sheets/) is a cloud-based\nspreadsheet solution with real-time collaboration and powerful tools to\nvisualize, process and communicate data.\n\nYou can extend Sheets with add-ons that build customized workflow improvements,\nestablish connectivity to third-party systems, and integrate your Sheets data\nwith other Google Workspace applications (like\nGoogle Slides).\n\nYou can see the Sheets add-ons others have built on the\n[Google Workspace Marketplace](https://workspace.google.com/marketplace/category/works-with-spreadsheet).\n\nWhat you can do\n---------------\n\nHere are a few things you can do with an add-on that extends Google Sheets:\n\n- You can read, edit, visualize, and format data in Google Sheets spreadsheets using the built-in Apps Script [Spreadsheet service](/apps-script/reference/spreadsheet). The service also lets you create and modify conditional formatting and data validation rules.\n- You can use the Apps Script [advanced Sheets service](/apps-script/advanced/sheets) to access the [Google Sheets API](/workspace/sheets/api) directly.\n- You can create [custom menus](/workspace/add-ons/concepts/menus) and define multiple [custom dialogs and sidebars](/workspace/add-ons/concepts/dialogs) interfaces using standard HTML and CSS.\n- You can include [custom function](#custom_functions) definitions in your add-on.\n- You can use add-ons [triggers](#triggers) that run specified functions when certain triggering events occur.\n\nSheets add-ons are built using Apps Script. To learn more about how to access\nand manage Google Sheets with Apps Script, see\n[Extending Google Sheets](/apps-script/guides/sheets).\n\nSheet structure\n---------------\n\nA Google Sheets spreadsheet consists of one or more sheets. Each sheet is\nessentially a 2D grid of cells into which text, numbers, links, or other\nvalues can be stored. A group of one or more adjacent cells is called a\n*range*.\n\nThe Apps Script [Spreadsheet service](/apps-script/reference/spreadsheet)\nprovides several classes to represent organizational structures in Sheets\n(such as [`Sheet`](/apps-script/reference/spreadsheet/sheet) and\n[`Range`](/apps-script/reference/spreadsheet/range)). You can use these\nclasses to read and modify Sheets data and behavior.\n\nTriggers\n--------\n\nApps Script [triggers](/workspace/add-ons/concepts/editor-triggers) let a script project\nexecute a specified function when certain conditions are met, such as when a\nspreadsheet is opened or when an add-on is installed.\n\nSee [add-on triggers](/workspace/add-ons/concepts/editor-triggers) for more information\non what triggers can be used with Sheets add-ons and what restrictions apply\nto their use.\n\nCustom functions\n----------------\n\nGoogle Sheets has a number of\n[built-in functions](https://support.google.com/docs/table/25273?ref_topic=1361471)\nlike `SUM` and `AVERAGE` that can be invoked from within a Google Sheet cell.\nSheets add-ons can define additional\n[custom functions](/apps-script/guides/sheets/functions) to supplement these\nbuilt-in functions. When a user\ninstalls the add-on, any defined custom functions included with the add-on\nbecome available immediately. It is possible for an add-on to consist of\nonly custom function definitions. Custom function definitions are primarily\nshared with others by publishing an add-on containing the definitions.\n\n### Creating add-on custom functions\n\nAny function defined in an add-on script project can be used as a custom\nfunction. Once the function is implemented and the add-on is installed, you\ncan call the custom function like any other built-in Sheets function: in a\nSheet cell, enter the `=` followed by the name of the function and any required\nparameters. If there are no errors, the result returned by the function is\nplaced in the Sheet cell, overflowing to neighboring cells as necessary.\n\nWhen creating custom functions in an add-on you should follow\nthe general custom function guidelines:\n\n- [Function naming guidelines](/apps-script/guides/sheets/functions#naming)\n- [Defining function arguments](/apps-script/guides/sheets/functions#arguments)\n- [Defining the function return value](/apps-script/guides/sheets/functions#return_values)\n- [Custom function data types](/apps-script/guides/sheets/functions#data_types)\n- [Enabling autocomplete using JSDoc](/apps-script/guides/sheets/functions#autocomplete)\n- [Services custom functions can use](/apps-script/guides/sheets/functions#using_apps_script_services)\n- [Optimizing custom functions](/apps-script/guides/sheets/functions#optimization)\n\nIn addition, custom functions defined in add-ons have some special\nconsiderations:\n\n- When naming your function, try to create a unique name, perhaps related to the name of your add-on. If two or more installed add-ons define custom functions with the same name, users can only use one of them.\n- Your add-on should clearly communicate what custom functions it provides. Be sure to provide accurate JSDoc comments for your custom functions so that Apps Script can present [autocomplete](/apps-script/guides/sheets/functions#autocomplete) information to the user. In addition, consider providing additional documentation of the custom functions either in the add-on itself or on an add-on support web page.\n- Custom functions that don't complete in under 30 seconds fail with an `Internal error executing the custom function` error. Build a good user experience by limiting the amount of processing you do in a custom function. [Optimize](/apps-script/guides/sheets/functions#optimization) the function where you can.\n- Custom functions can't use Apps Script services that require authorization, and fail with a `You do not have permission to call X service` error if this is attempted. Only use the [permitted services](/apps-script/guides/sheets/functions#using_apps_script_services) in your custom function.\n- Each custom function in a sheet results in a separate call to the Apps Script servers. If a user attempts to use custom functions in too many cells, the functions may execute slowly. To mitigate this, keep your custom functions as simple as possible. If you need the function to perform complex or extended processing, don't use a custom function---provide that functionality via a menu item, dialog, or sidebar interaction instead.\n\nSheets macros\n-------------\n\n[Macros](https://support.google.com/docs/answer/7665004) let you record actions\ntaken in Google Sheets and repeat them later with a keyboard shortcut. When a\nmacro is created in a sheet, it is added as a *macro function* in an Apps\nScript project [bound](/apps-script/guides/bound) to that sheet. For more\ninformation about macros, see\n[Google Sheets macros](/apps-script/guides/sheets/macros).\n\nUnfortunately, Sheets macros *can't* be distributed with add-ons. If you include\na macro definition in an add-on's manifest, it is unavailable to users of that\nadd-on."]]