To provide technique capable of raising the internal temperature of a fuel cell in a short time in low temperature starting while suppressing rising of the manufacturing cost of the fuel cell.

A fuel cell system is equipped with a fuel cell; a cooling medium passage through which a cooling medium for cooling the fuel cell flows; a cooling medium flow device for making flow the cooling medium in the cooling medium passage; and a control part controlling operation of the cooling medium flow device. The control part controls the cooling medium flow device so as to conduct starting mode operation which does not make flow a cooling medium when starting temperature of the fuel cell is lower than a prescribed value, and makes flow the cooling medium when starting temperature is at the prescribed temperature or higher, in starting of the fuel cell system.