A charging system includes a locking device locking a connector provided at the end of a cable in the state where the connector is connected to an inlet provided in a vehicle; a release button for releasing locking by the locking device; a switch generating a signal indicating that the connector and the inlet are connected; a horn; and an ECU. In response to the operation of the release button, the switch stops generation of the signal. The ECU controls charging of a power storage device and detects whether the signal is issued or not. In the case where the ECU detects that generation of the signal is stopped during charging of the power storage device, the ECU causes the horn to issue an alarm.