PURPOSE: To provide an illumination switch which consumes no electricity by forming a light accumulative ink layer on either a key top itself or a member of a switch set on the opposite to the lower face of a key top.

CONSTITUTION: A key top 1 is formed unitedly with a rubber plate 10 made of, for example, silicone rubber and a light accumulative ink is applied to the upper face of the key top 1 to form a light accumulative ink layer 11. A skirt part 12 which is elastically deformable is put between the key top 1 and the rubber plate 10 to operate the key top 1 up and down. A conductive layer 14 is also formed on a projected part 13 in the back side of the key top 1 and the layer 14 is made possible to be brought into contact with a contact point 15 of a switch to send a contact signal. A key cap 16 made of a transparent resin material to prevent adhesion of dirt from the hands, etc., is put on the upper face of the ink layer 11.