FUEL CELL AND OPERATING METHOD FOR FUEL CELL

PROBLEM TO BE SOLVED: To prolong the useful life of a cell, by making it possible to maintain quantity of phosphoric acid held by an electrolyte matrix over a long period of time even without providing a mechanism or the like for replenishing phosphoric acid is not provided in the case of a phosphoric-acid type fuel cell. SOLUTION: A controller 4 calculates a control temperature corresponding to a value of a load equating to a detected value (load) of an ammeter 42 by referring to a table 43. An output of an air fan 3 is controlled so as to cause a cell operation temperature (temperature detected by a temperature sensor 50) to agree with the calculated control temperature and, by such control, the operation temperature of a fuel cell body 1 is regulated in accordance with the load such that a weight variation of the fuel cell body 1 during operation is lessened.