A keyboard device for an electronic keyboard instrument, making uniform an upper surface height of the rear end of each key in contact with a hammer in a key-released state. The keyboard device includes longitudinally extending wooden keys capable of swinging and laterally juxtaposed, a hammer support disposed rearward of the keys, longitudinally extending hammers having a rear end thereof supported by the hammer support vertically pivotally movably and a protrusion protruding downward from a lower surface thereof for contact with a rear end of an associated key, and hammer contact height-regulating parts each made of a synthetic resin and mounted on the rear end of each key, the part being in contact with the protrusion in the key-released state, to regulate a contact height of the protrusion to a predetermined height.