A keyboard device capable of reconstructing a unique clicking sense of an acoustic piano is provided. A first incline portion (a plane or curved surface) of a sliding surface is inclined towards a direction gradually departing from a base portion of a protrusion along a displacement direction of the protrusion in a key-pressing operation for reducing a resistance exerted on the protrusion and suppressing a gradual increase of a sense of resistance. Moreover, a bump portion located at where the protrusion reaches after sliding through the first incline portion is used to increase the resistance exerted on the protrusion for increasing the sense of resistance. When the protrusion crosses over the bump portion, the sense of resistance is reduced. Accordingly, variation in the sense of resistance before and after the bump portion is increased, and the unique clicking sense of the acoustic piano is reproduced.