Provided is a keyboard device that can suppress a reduction in the operability of a key. A rear guiding member comprises a pair of guiding surfaces that, in a side view of a key, face forward and rearward and are formed along an arc that is convex toward the front. The key comprises a pair of sliding surfaces that slide against the pair of guiding surfaces. Due to this sliding of the guiding surfaces and the sliding surfaces, rotation of the key can be guided while displacement of the key in the front-rear direction is regulated. Consequently, because forward and rearward displacement of the key during key pressing can be suppressed, a reduction in operability (feeling of touch) during pressing of the key can be suppressed.