Provided is a membrane electrode assembly for a proton exchange membrane water electrolyzer, including: an oxygen electrode including an iridium oxide (IrO2) layer which is an electrodeposited oxygen electrode catalyst layer on a titanium (Ti) layer which is a diffusion layer; a hydrogen electrode in which a hydrogen electrode catalyst layer is formed on a diffusion layer; and an electrolyte membrane placed between the oxygen electrode catalyst layer and the hydrogen electrode catalyst layer, in which a portion of the pores of the Ti diffusion layer are filled with an electrolyte of the electrolyte membrane.