To provide a composite key apparatus that can make clearance between keys small and realize a high quality of key apparatus without increasing the number of parts and the number of assembling processes.

It is constituted by an aperture 21 for inserting and passing an elliptical hinge key in the middle of a seesaw key 20, an axis part 22 on the extended line of the elliptical short diameter, the seesaw key 20 having an implanted pin in order to transmit a key pressing operation on it, a boss 33 into which a cylindrical aperture is formed in order to receive the pin, a hinge key 30 having a hinge part 31 inserting and passing a key top into the hinge key and molded integrally with the key top, a key frame member 40 holding bearing part 41 receiving the axis part 22 and the hinge part 31, and a printed circuit board 50 having a switch member 51 fixed to the under case 90.