GUISkin.horizontalScrollbarLeftButton

public GUIStyle horizontalScrollbarLeftButton ;

説明

GUI.HorizontalScrollbar の左側のボタンで使用されるスタイル

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public float hSbarValue;
    public GUIStyle style;
    void OnGUI() {
        GUI.skin.horizontalScrollbarLeftButton = style;
        hSbarValue = GUILayout.HorizontalScrollbar(hSbarValue, 1.0F, 0.0F, 10.0F);
    }
}