Disclosed are a membrane electrode assembly with a sub-gasket and a manufacturing method thereof. The membrane electrode assembly includes an electrolyte membrane, the sub-gasket formed in an edge region of the electrolyte membrane to surround a central region of the electrolyte membrane, and an adhesive layer formed between the electrolyte membrane and the sub-gasket and including an adhesive material and an antioxidant. The electrolyte membrane is formed to have a flat surface in a first direction, the sub-gasket extends in the first direction and a second direction vertical to the first direction, and the antioxidant includes a metal salt hydrate.