A vehicle door lock system has a lock mechanism for locking or unlocking the vehicle door. A control mechanism for controlling an operation of the lock mechanism includes first and second resonators. The first resonator resonates at a predetermined first value Q for transmitting a first signal to the outside of the vehicle. The second resonator is connected in series with the first resonator and resonates at a second value Q which is greater than the first value Q, and changing a resonant condition in accordance with a change of a capacitance. A single actuator is provided for actuating the first and second resonators. A switching mechanism is provided which utilizes the actuator for alternatively switching actuation between the first and the second resonators. The control mechanism controls the switching operation of the switching mechanism and the operation of the door lock mechanism in accordance with the resonant condition of the second resonator.