[Problem] To provide a catalyst which has high oxygen reduction activity, also has excellent durability, and is inexpensive and excellent in electric power generation cost as compared with noble metal catalysts such as platinum.[Solution to problem] A catalyst for a polymer electrolyte fuel cell, including a graphitized carbon powder and a niobium oxycarbonitride or a titanium oxycarbonitride as an active substance, and a polymer electrolyte fuel cell using the catalyst.