A lock device includes a lock member moved between a lock position, at which the lock member restricts removal of a locking subject from a power port, and an unlock position, at which the lock member permits removal of the locking subject from the power port. A transmission member is moved between a first position, at which the transmission member fixes the lock member at the lock position, and a second position, at which the transmission member permits movement of the lock member to the unlock position. A auxiliary unlocking mechanism includes a movable forcible unlocking member, which manually moves the transmission member to the second position, and a holding unit, which holds the forcible unlocking member while permitting such movement. The auxiliary unlocking mechanism may be used should there be failure of the main unlocking mechanism.