PURPOSE: To perform purging of a fuel chamber and an air chamber of a fuel cell main body always securely, to make acceptance and inventory control of a purging gas unnecessary, and to make accessory equipment compact by always storing high purity nitrogen gas separated and condensed from atmosphere.

CONSTITUTION: Air in the atmosphere is drawn through a dust removing filter 41 of a purging gas manufacturing apparatus 40 and is compressed to 7kg/cm2 G with a compressor 42. High purity nitrogen gas of 7kg/cm2 is then separated and condensed with a gas separator film 44 of a hollow thread shape and made with polysulfone resin and is stored in a reservoir tank 45. When power generation with a fuel cell main body 10 is stopped, a fuel chamber 12 and an air chamber 13 are purged with the nitrogen gas through a valve 46 of a piping 48 and through a valve 47 of a piping 49. Thus, acceptance and inventory control of the purging gas becomes unnecessary, making accessory equipment compact.