To provide a polymer electrolyte fuel cell excelling in durability, and capable of exerting sufficient power generation performance by keeping an excellent gas diffusion property for electrode catalyst layers even in a high humidification operation.

This polymer electrolyte fuel cell is provided, on both sides of an electrolyte membrane 10 made of a solid polymer, with the electrode catalyst layers 12 and 22 formed with an electrode catalyst with catalyst particles supported to a carbon support, and a proton conducting electrolyte, and also provided, between the electrolyte membrane 10 and at least one of the electrode catalyst layers 12 and 22, with water retention layers 11 and 22 each containing a carbon support and a proton conducting electrolyte, and having water retentivity higher than those of the electrode catalyst layers 12 and 22. Power generation performance and durability are improved by smoothly moving water in the electrode catalyst layers to the water retention layers.