PURPOSE: To attain dialing without direct finger contact by forming the dialing part by a photosensitvie means.

CONSTITUTION: A light pen 5 is provided with a light emitting element 8 and a switch 9 lighting the element 8. The light pen 5 is removed from a telephone set 1 and the light emitting element 8 is moved to a position is opposition to a photodetector 7 in the order of dial number to depress a switch 9. The photodetector 7 senses an optical pulse from the light emitting element 8 to send a photodetection signal to a receiver built in the telephone set and the receiver identifies the dial number by using the photodetection signal. Since the optical signal from the light pen 5 is a special signal, the receiver discriminates the dialing signal from the background light such as light from a fluorescent light in a room. Thus, contactless dialing is applied and phe convenience of the telephone set is enhanced.