To solve a problem in which a fuel cell system having a fuel recycling system requires many branch pipes to a separator for separating water out of discharge fuel from a stack, to a combustion device, and to a fuel discharge system, causing the device to be big and complex which in turn impairs maintainability.

The fuel cell comprises an inlet port 23 for introducing unused fuel discharged from the fuel cell stack to a water separation chamber inside a separator body 21, and distribution ports 24-26 for distributing the unused fuel from the water separation chamber to three systems including a fuel circulation passage 18, discharge passage 12, and combustion device passage 7. The distribution ports for the fuel cycling passage and the combustion device passage are arranged in opposition to the inlet port with the water separation chamber inside the separator in-between and the discharge passage is arranged in the same side as the inlet port.