Abstract: A switch device includes a key member (4). The key member (4) has a display switch button (13) including a transparent portion through which image information displayed on a display screen of an image display device is transmitted so as to display the image information on an outer side surface of the key member (4). Further, the key member (4) has a button mounting frame (16) including a switch depressing portion (14) operative to switch a switch (6) when the key depressing portion (14) is depressed, and having a button mounting hole portion to which the display switch button (13) is attached. Furthermore, the key member (4) has a waterproof dust cover (19) of a rubber material, which is molded integrally on the button mounting frame (16) to cover the same, and which includes a support portion (17) held in intimate contact with the display screen, and a contractible skirt portion (18). A plurality of resin filling holes are formed in the button mounting frame.