Fuel cell stack

A fuel cell stack comprising:

• a cell assembly formed of a stacked unit cells, each composed of a membrane electrolyte assembly and separators which sandwich the membrane electrolyte assembly;
• a pair of collector plates A and B which sandwiches the cell assembly;
• a pair of end plates A and B which sandwiches the cell assembly and the collector plates;
• and
• an elastic member disposed between end plate A and collector plate A,
• wherein end plate A has a convexed portion and a concaved portion on a surface facing collector plate A, and
• the concaved portion of end plate A holds therein the elastic member,
• a bottom surface of the concaved portion includes a second convexed portion and a second concaved portion so that a part of a surface of the elastic member facing end plate A does not contact with the end plate A, and
• the elastic member contacts with a second convexed portion of the end plate A.