Whether a gas leakage occurs or not is accurately determined in a simple configuration. When receiving a request for activation of a fuel cell, a control unit opens a main shutoff valve to start hydrogen gas supply from a hydrogen tank to the fuel cell. The control unit thereafter performs gas leakage determination processing for a hydrogen piping system. If it is determined in the gas leakage determination processing that a gas leakage occurs, a gas leakage alert is output to stop the activation of the fuel cell. If it is determined in the gas leakage determination processing that a gas leakage does not occur, a compressor is activated to start oxidant gas supply to the fuel cell, and the fuel cell continues being operated.