A fuel cell comprises an membrane electrode assembly formed by holding an electrolyte membrane between a pair of electrodes and a separator layered on both sides of the membrane electrode assembly for forming gas passages between the separator and the electrode. The separator includes protrusions formed on both surfaces thereof for contacting with the electrode, and a spacer portion disposed between the protrusions for substantially forming the gas passage. The protrusions and the spacer portions are arranged along a surface direction of the separator so as to form a corrugated plate. At least two drawn portions in which thickness of the spacer portion changes to a thin portion are formed between the protrusions in the spacer portion.