To install a receiver or an antenna in the most favorable receiving environmental position, by providing an on-board receiver with a role as a receiver for receiving control signals of electrical instrument units equipped in a vehicle.

A receiver 2 for an on-board keyless entry system or an antenna 3 for the receiver 2 is built in or attached to either indicator visually instructing various information given in the vehicle or control device, by which electrical instrument unit 7, 8, 9, 17 can be changed over. The receiver 2 is provided with a role as a receiver for receiving control signals of the electric instrument units 7, 8, 9, 10, 17. The indicator or the control device and the electric instrument units 7, 8, 9, 10, 17 are connected through a signal line 6. Accordingly, the receiver or the antenna can be installed in the most favorable receiving environmental position, and a steadly stable receiving reliability can be secured.