To secure a stoichiometric ratio even when the motor temperature of a circulation pump rises.

A first detection line 102 which is set on a lower temperature side than a limit line 104 expressing an upper temperature of a motor 60 permitted by an inverter 62 shows a motor temperature which becomes a criterion in which a control part 54 switches over from reutilization of hydrogen by a circulation pump 28 into increase in hydrogen concentration, as a means for securing the hydrogen stoichiometric ratio against a demand output of a fuel cell 10. The control part 54, when the motor temperature exceeds the first detection line 102 against the demand output of the fuel cell 10, suppresses increase in the number of rotation of the motor 60 and adjusts opening degree of a shut valve 22 and a regulator 23 and increases the concentration of hydrogen to be supplied from a hydrogen tank 21 to the fuel cell 10 to raise the supply pressure of hydrogen. Thereby, rising of the motor temperature is suppressed and the hydrogen stoichiometric ratio can be secured.