PURPOSE: To readily and surely mount a multiplicity of keys with less number of parts by using an insulation type elastic member which is secured with a conductive member at the end part.

CONSTITUTION: An insulation type elastic switch member 40 which is secured with a conductive member 41 at its end 41 is assembled together with keys 10, inside and outside circumferential rings 50, 60, stopper parts 30 into the upper case band 20 of a case. Then, when the key 10 is pressed, the key end part 12 depresses the elastic switch member 40 until its collar part 11 contacts the stopper member 30 and the conductive member 41 is pressure contacted to the contact part 71 of a module 70. When the key 10 is released, the key 10 is ascended and reset until its collar part 11 contacts the inside wall face 21 by the restoring force of the elastic switch member 40. And by disposing a multiplicity of keys 10 along the elastic switch member 40, the intended object may be achieved.