A membrane electrode assembly of an embodiment includes: a first electrode having a first base, and a first catalyst layer provided on the first base, the first catalyst layer including a plurality of first catalyst units with a laminated structure, and the laminated structure including void layers; and an electrolyte membrane being in direct contact with both first surfaces of the first catalyst units facing each other among the first catalyst units, and second surfaces of the first catalyst units on the opposite side from the first base side. A portion is included where the electrolyte membrane exists over a region being at least 80% of a thickness of the first catalyst layer from the second surfaces of the first catalyst units toward the first base.