A lock system includes a lock device arranged in at least a vehicle. The lock device includes a lock member movable between a lock position and an unlock position. The lock device locks a lock subject to the vehicle when the lock member is located at the lock position and unlocks the lock subject when the lock member is located at the unlock position. A controller, which performs power line communication, includes a request output unit that transmits an operation request to the lock device by performing the power line communication to switch the lock subject between a locked state and an unlocked state. The lock device includes a lock control unit that receives the operation request from the controller and controls movement of the lock member based on the operation request.