The present invention provides a membrane electrode assembly for a polymer electrolyte fuel cell, including: an electrolyte membrane; a catalyst layer; and a conductive porous gas diffusion layer, in which an interface between the catalyst layer and the electrolyte membrane is provided with a groove for allowing one of passage and retention of a fluid, and a polymer electrolyte fuel cell employing the membrane electrode assembly. As a result, there is provided at low costs the membrane electrode assembly for a polymer electrolyte fuel cell having improved drainage performance and the polymer electrolyte fuel cell employing the membrane electrode assembly and having stable power generation performance.