Separator for fuel cell and single cell for fuel cell

A separator for a fuel cell, the separator including a facing surface configured to face a power generating unit of the fuel cell, groove passages through which a reactant gas flows being arranged side by side on the facing surface, wherein

• a direction in which the groove passages are arranged side by side is defined as an arrangement direction,
• ribs, which are located between the groove passages and protrude toward the power generating unit, are provided on the facing surface, and
• at least one of the ribs includes at least one protrusion that protrudes toward the power generating unit, and wherein
• the rib includes a recess in a center of the rib in the arrangement direction of the groove passages,
• the recess includes:
• a bottom surface that extends in a planar direction of the power generating unit and faces the power generating unit;
• and
• two inner side surfaces that extend from opposite ends in the arrangement direction of the bottom surface,
• the two inner side surfaces are inclined such that a given point on each inner side surface separates further away from the bottom surface in the arrangement direction as that point approaches the power generating unit in a facing direction in which the power generating unit and the separator face each other, and
• the recess is provided at a position that does not overlap with the protrusion in an extending direction of the rib.