ELECTROCHEMICAL OXYGEN REDUCTION CATALYST, AIR ELECTRODE, FUEL CELL, AND METAL-AIR CELL

There is provided an electrochemical oxygen reduction catalyst including metal particles having oxygen reduction activity, an additive, and primary particles of a carrier having pores, in which the additive is at least one organic nitrogen compound, the metal particles are supported on the carrier, and in a case where metal particles that are present on an outermost surface of the primary particles of the carrier are defined as outer particles, and metal particles that are present on an inner side of the outermost surface of the primary particles of the carrier are defined as inner particles, a ratio of a total surface area of the outer particles to a total surface area of the inner particles (the total surface area of the outer particles/the total surface area of the inner particles) is 0.36 or more.