A fuel cell stack (1) generates power by an electrochemical reaction between hydrogen and oxygen in plural stacked fuel cells (2a, 2b). Each fuel cell (2a, 2b) comprises an anode (26a) to which hydrogen is supplied, a cathode (26b) to which air containing oxygen is supplied, and a electrolyte membrane (20) which conducts hydrogen ions from the anode (26a) to the cathode (26b). The fuel cells (2a, 2b) comprise center cells (2a) and end cells (2b). By arranging the moisture absorption capacity of the end cells (2b) to be larger than that of the center cells (2a), flooding in the end cells (2b) which do not easily rise in temperature is prevented, and the low-temperature start-up performance of the fuel cell stack (1) is enhanced.