PURPOSE: To improve the safety and reliability of fuel battery equipment by controlling the temperature difference of cooling water at inlet and outlet to be the same using a cooling water distribution controller.

CONSTITUTION: Many laminated element batteries are divided into blocks by a definite number. To each block, a cooling water piping is connected and on the inlet side of each cooling water piping, cooling volume control valves 121, 122, 123 are connected. At the inlet and outlet of the cooling water piping, temperatures of the cooling water are measured and the temperature difference between them is detected. Furthermore, a cooling water distribution controller 17 is provided to control the volume of cooling water fed to each block of fuel battery bodies 81, 82, 83 through the cooling volume control valves 121, 122, 123. The temperature difference of cooling water at the inlet and outlet of each block is controlled to keep the same value. By the arrangement, breakdown of fuel battery due to the inhomogeneous distribution of cooling water can be prevented.