A cathode catalyst layer has two layers: a first catalyst layer on a gas diffusion layer side, and a second catalyst layer on an electrolyte membrane side. The first catalyst layer includes a first particulate conductive member, first catalyst particles, and a first fibrous conductive member, at least part of the first catalyst particles being supported on the first particulate conductive member. The second catalyst layer includes a second particulate conductive member and second catalyst particles, at least part of the second catalyst particles being supported on the second particulate conductive member. A catalyst support density D2 of the second catalyst particles on the second particulate conductive member is greater than a catalyst support density Di of the first catalyst particles on the first particulate conductive member.