Lock device and electronic key system

A lock device is arranged in a vehicle (1) including an inlet (34) used for charging. The vehicle (1) is configured to perform a predetermined control operation in accordance with a control request signal transmitted through wireless communication from an electronic key (80) when a normal operation is performed on a control switch (85; 86) of the electronic key. The lock device includes a lock mechanism (32, 33) configured to switch a locking subject (10; 36) related with the inlet between a lock state and an unlock state. A controller (11) controls the lock mechanism to switch the locking subject between a lock state and an unlock state when detecting a special operation performed on the control switch (85; 86).