Disclosed is a keyboard device 100, in which a plurality of keys 3 are attached to a keyboard chassis 1 rotatably in a keying direction. In the keyboard device 100, a key pressing member 20 of the keyboard chassis 1 includes sliding portions 26 as protruding parts. Chassis attachment portions 36 of the keys 3 include opening portions 36a as recessed parts. A configuration is adopted so that, in a state where the sliding portions 26 and the opening portions 36a are engaged with other, the keys 3 can be prevented from dropping off from the keyboard chassis 1, and inclination of the keys 3 in a transverse direction can be suppressed.