A keyboard apparatus 100 has plural keys 10 and 11, plural electronic actuators 30, and plural link mechanisms 40. Each of the keys 10 and 11 extends in the longitudinal direction, and pivots in the vertical direction about a support C1 by the operation of depressing the keys and the operation of releasing the keys. Each of the electronic actuators 30 has a movable member 31 that displaces in the vertical direction in interlocking with the pivot movement of each of the keys, and applies a reaction force against the operation of depressing the keys 10 and 11. Each of the link mechanisms 40 links each of the keys 10 and 11 and the movable member of each of the electronic actuators 30 in such a manner that power can be transmitted. Each of the link mechanisms 40 has a plate-like first fixing portion 41 that is fixed to each of the keys, a plate-like second fixing portion 42 that is connected to each of the movable members 31, and plural spherical fine grains 43 filled in a gap between the first fixing portion 41 and the second fixing portion 42.