A keyboard structure capable of suppressing a depth dimension of a keyboard instrument and rearward displacements of key main bodies to thereby prevent plastic deformation of hinges. White and black key main bodies are each disposed for pivotal motion around a common base end, serving as a key fulcrum, in a key depression/release direction via a hinge extended therefrom vertically downward. A rear stopper is provided in an intermediate portion of a key frame, and a contact portion of a stopper contact member is in light contact with a front surface of the rear stopper when a key main body is in a key depression initial position. In a key-nondepressed state, when a rearwardly force is applied to a key main body, the rear stopper applies the contact portion with a forwardly force against the rearwardly force, thus suppressing a rearward displacement of the key main body.