GAS DIFFUSION ELECTRODE BASE MATERIAL AND PRODUCTION METHOD THEREFOR, AND SOLID POLYMER FUEL CELL

A fuel cell with high productivity, high power generation performance and high durability is described, along with a gas diffusion electrode base material having a microporous layer on one side of an electrically conductive porous base material, where the electrically conductive porous base material contains carbon fiber and resin carbide and has a density of 0.25 to 0.39 g/cmand a pore mode diameter in a range of 30 to 50 μm. The microporous layer contains a carbonaceous powder and a fluororesin and has a surface roughness of 2.0 to 6.0 μm, a porosity of 50 to 95%, and a pore mode diameter of 0.050 to 0.100 μm.