An air conditioner capable of creating an indoor environment without a reduction in oxygen concentration even if a person is present in a room by taking fresh oxygen from the outside to the inside of the room. An indoor unit is connected to an outdoor unit, and a solid electrolyte type oxygen pump in which electrode film is formed on both faces of a solid electrolyte body is disposed on the outdoor unit. Oxygen generated by the solid electrolyte type oxygen pump is supplied to the indoor unit side.
