The present invention includes a keyboard chassis 1; keys 2 which are arranged on the keyboard chassis 1 and rotate in an up and down direction by bending a bendable section 22 positioned in the rear; and a key rotation holding section 30 for holding the rotation fulcrum of a key 2 stable when it rotates in the up and down direction. Accordingly, the rotation fulcrum of the key 2 is kept stable by a first supporting section 31 and a second supporting section 32 of the key rotation holding section 30 when the key 2 is depressed and the bendable section 22 bends in the up and down direction, whereby the key 2 is stably rotated. Therefore, regardless of whether the front portion of the key 2 is being depressed or the rear portion thereof is being depressed, the rotation movement of the key 2 will always remain stable.