An electrode substrate for a fuel cell including a diffusion layer, a first microporous layer that embeds into the diffusion layer, with the first microporous layer having a thickness in the range of 10 to 30 .mu.m, and a second microporous layer that forms a boundary with the diffusion layer on the surface of the first microporous layer. The electrode substrate has improved performance such as increased diffusion properties of a fuel or an oxidant, increased properties of releasing moisture, and enhanced electron conductivity.