To make it possible to automatically lock or unlock a door without making switch operation by a driver.

When a driver having a key gets off the car, in the case a door on a driver's seat side is closed once after it is opened (affirmed with step 201), an identification code is started to receive (steps 208 and 210). While, when the driver holds the key, a specific electric circuit is short circuited, and when a regular switch is not operated within a specific time, an auxiliary identification code is automatically transmitted. The auxiliary identification code is received (affirmed with the step 21), and when the auxiliary identification code is consistent with a registration code established in advance (affirmed with step 218), after all doors are closed (affirmed with step 220), a door lock driving device is so controlled (step 220) that all doors are locked.