Abstract: A stack that is supplied with reform gas containing hydrogen that is produced by a reformer by reforming source fuel to serve as anode gas and air containing oxygen to serve as cathode gas, and it performs power generation. The stack has a circulation channel for stack cooling water through which the stack cooling water flows for maintaining he temperature of the stack. There is a first heat exchanger that performs heat exchange between anode exhaust gas and exhaust gas recovery water; a second heat exchanger that performs heat exchange between cathode exhaust gas and the exhaust gas recovery water; a third heat exchanger that performs heat exchange between the stack cooling water and the exhaust gas recovery water; and a fourth heat exchanger that performs heat exchange between the reform gas and the exhaust gas recovery water. These heat exchangers are disposed in series in a channel of the exhaust heat recovery water.