Version: 2018.2
public bool alt ;

説明

「 Alt/Option 」キーが押されたかどうか(読み取り専用)

On Windows, this returns true if any Alt key is held down.
On Mac, this returns true if any Option key is held down.

using UnityEngine;

public class Example : MonoBehaviour { // Prints Option or Alt key was pressed depending the // platform this script is being run. void OnGUI() { Event e = Event.current; if (e.alt) { if (Application.platform == RuntimePlatform.OSXEditor) { Debug.Log("Option key was pressed"); } else if (Application.platform == RuntimePlatform.WindowsEditor) { Debug.Log("Alt Key was pressed!"); } } } }