A compressor and an air conditioner including the same having an improved structure capable of decreasing a discharge temperature of the compressor. The compressor which compresses and discharges refrigerant includes a casing defining an external appearance thereof, at least one cylinder including an inner space, a rolling piston which eccentrically turns in the inner space, a vane which radially abuts the rolling piston and divides the inner space into a suction chamber and a compression chamber, and a vane chamber recessed outward of the inner space such that the vane advances and retreats, a plurality of plates disposed above and below the at least one cylinder so as to define the inner space, an injection line provided in one of the at least one cylinder and the plural plates, and a check valve installed on the injection line.