PURPOSE: To enable a desired door or the like to be locked or unlocked corresponding to a signal in its transmitted position by transmitting with a single transmitting means and a single switch operation from outside a vehicle toward its inside the signal received by a receiver.

CONSTITUTION: A receiver 12 has three light receiving parts 21 to 23 arranged toward both right and left sides and the rear of a car body. The receiver 12 forms in its inside tapered openings 24 to 26 respectively of opening angle θ1, θ2, θ3 in each light receiving part 21 to 23 further arranges in its internal part light receiving elements 27 to 29 respectively consisting of, for instance, a photodiode. Each light receiving element 27 to 29 can well receive an infrared ray code signal from a transmitter 18 in light receiving areas 31 to 33 set respectively in the vicinity of respectively a driver's seat side door 2, assistant driver's seat side door 3 and a trunk lid 4 with the receiver 12 serving as the center toward both the sides and the rear of the car body so as to be prevented from interfering with each other. Accordingly, a control unit 11 selects a desired door or the like enabled to be locked or unlocked by operating the transmitter 18 in any of the light receiving areas 31 to 33.