Patent ID: 7138978

Claim:
A key input device in which an input key can be oscillated with respect to an opposing surface facing a bottom portion thereof and in which depression of the opposing surface with the input key at a normal operating point situated above a contact portion of a board causes the input key to be tilted in a normal oscillating direction to effect input at the contact portion, wherein one of the bottom portion of the input key and the opposing surface is equipped with guide protrusions arranged symmetrically with respect to an imaginary line extending along the normal oscillating direction of the input key, wherein depression of the opposing surface with the input key at an erroneous operating point deviated from the normal operating point results in the guide protrusions guiding the input key so as to be tilted in from an erroneous oscillating direction to the normal oscillating direction while abutting one of the bottom portion of the input key and the opposing surface, and wherein the input key is a film-integrated-type resin key top obtained by forming a key top main body of resin integrally on the back side of a resin film whose front side constitutes a depressing operation surface.