Patent ID: 8088531

Claim:
A fuel cell system, comprising: a fuel cell; a fuel gas supplying path connected to the fuel cell, the fuel gas supplying path supplying a fuel gas to the fuel cell; an oxide gas supplying path connected to the fuel cell, the oxide gas supplying path supplying an oxide gas to the fuel cell; a regulator arranged on at least one of the fuel gas supplying path and the oxide gas supplying path; a bypass path that communicates an upper stream side path of the regulator with a lower stream side path of the regulator; and a pressure controlling valve arranged on the bypass path, wherein the pressure controlling valve closes in a case where the pressure difference between the upper stream side path and the lower stream side path is less than a predetermined amount, and the pressure controlling valve opens in a case where the pressure difference between the upper stream side path and the lower stream side path exceeds the predetermined amount, wherein the pressure controlling valve is configured to be mechanically opened and closed by the pressure difference between the upper stream side path and the lower stream side path.