A lever 40 is supported by a lever supporting portion 41. The lever 40 is urged by a first spring 45 and a second spring 46. The urging force of the first spring 45 varies over the entire operational range of the lever 40. The second spring 46 and a third spring 47 are provided serially through a movable supporting member 48. The displacement of the movable supporting member 48 is restricted by a fixed supporting member FR. If the urging force of the second spring 46 exceeds the urging force of the third spring 47, the restriction on the displacement of the movable supporting member 48 is removed. Therefore, the present invention provides a player with feeling similar to that the player perceives when he manipulates a damper pedal of an acoustic piano.