A gas diffusion electrode includes: an electrode catalyst layer; microporous layers arranged on the electrode catalyst layer and including at least second and first microporous layers, wherein the second microporous layer disposed on the electrode catalyst layer side is composed to have higher water repellency than the first microporous layer; and an oxidant gas diffusion substrate disposed on the microporous layers and formed of carbon fiber. According to the gas diffusion electrode of the present invention, drainability of generated water from the electrode catalyst layer to the gas diffusion layer and moisture retention and gas diffusibility of the electrode catalyst layer can be enhanced. Moreover, according to a solid polymer electrolyte fuel cell of the present invention, stable power generation characteristics can be obtained even under an operating condition with a wide humidity range and current density range.