Single cell for fuel cell

A single cell for a fuel cell, comprising:

• a power generating unit that includes a membrane electrode assembly and two gas diffusion layers, the gas diffusion layers holding the membrane electrode assembly in between;
• and
• two separators that hold the power generating unit in between, wherein
• each separator includes a facing surface that faces the power generating unit,
• each facing surface includes groove passages, which are configured to allow a reactant gas to flow therethrough, and ribs, the ribs being located between the groove passages and protruding toward the power generating unit,
• the ribs each include:
• a top wall portion that is in contact with the power generating unit;
• two side wall portions that are located at opposite sides of the top wall portion in an arrangement direction of the groove passages;
• and
• corner portions each located between the top wall portion and one of the side wall portions,
• a restricting portion is provided at a section of each corner portion that faces the groove passage, the restricting portion restricting the gas diffusion layer from sinking into the groove passage,
• the restricting portion is a conductive porous body, and
• the restricting portion continuously extends in the arrangement direction from one of two corner portions, which are arranged at opposite sides of the groove passage, to the other of the two corner portions along the gas diffusion layer.