A fuel cell (10) is formed by sandwiching a membrane electrode assembly (14) between first and second separators (16, 18). An oxygen-containing gas supply passage (20) extends through the fuel cell (10) in a stacking direction. The oxygen-containing gas passage (20) includes first and second straight sections (20a, 20b) to form a single opening. The first and second straight sections are elongated in directions indicated by arrows B and C around a corner at an upper portion of one end of the first separator (16).