Lock device

A lock device, comprising:

• a locking member configured to be moved between a lock position at which the locking member locks a locking subject and an unlock position at which the locking member unlocks the locking subject;
• a drive unit including:
• a movable member configured to be moved by a drive force, and
• a transmission mechanism configured to transmit the drive force to the movable member and move the movable member, wherein
• the movable member is configured to be moved in a movement state that is shifted between a relative movement state in which the movable member is moved relative to the locking member and an integral movement state in which the movable member is moved together with the locking member to move the locking member toward the lock position or the unlock position;
• a detector of which an output value varies in accordance with movement of the movable member or the transmission mechanism;
• and
• a controller that performs a failure determination based on a change in the output value,
• wherein the controller is configured to
• control driving of the drive unit,
• obtain the output value of the detector as a first output value when the drive unit starts operating,
• obtain the output value of the detector as a second output value during a period from when the first output value is obtained to before the drive unit stops operating, and
• perform the failure determination based on whether a differential value of the first output value and the second output value indicating the change in the output value exceeds a threshold value.