PURPOSE: To eliminate use of any tact switch and accomplish an uncostly key device by constructing it from a rubber part, in which a contact is formed on the undersurface of each slope of rubber key, and a base board in which a contact pattern is formed in its part mating with the contact of the rubber part.

CONSTITUTION: When the oversurface of a key top 1a constituting part of a multi-continuous key 1 is depressed, the joint of the key top 1a with a support 1b is deflected due to its hinge construction. Also joints of a rubber key 2a of multi-continuous rubber key with a support 2b and with a reinforcement 2c are deflected due to hinge construction to cause the rubber key 2a to rotate downward. Because the undersurface of the rubber key 2a is formed in such a slope that the thickness of the rubber key 2a reduces from the support 2b toward the reinforcement 2c, the whole surface of contact 3 formed at the undersurface of the slope of rubber key 2a is put in close contact with a contact pattern 5 on a base board 4, which allows the pattern 5 to be turned on certainly.