A keyboard device includes hammers 16w,16b that rock with the rocking movement of plural white and black keys 11w,11b. The plural white and black keys 11w,11b include drive units that drive the hammers 16w,16b. The drive unit is provided anterior or posterior to a front end of the key. A positional relationship between a plane including a key support portion of each white key 11w and black key 11b and the front end of the white key 11w and black key 11b, and a top face of each white key 11w and black key 11b is set such that the top faces of the plural white keys 11w and black key 11b are located on the same plane, when the rocking angles of the plural white keys 11w and black key 11b reach a predetermined angle respectively.