A container refrigeration apparatus includes: a casing (12) which forms an external storage space (S1) communicating with the exterior of the container (11) and an internal storage space (S2) communicating with the interior of the container (11); a refrigerant circuit (20); an external fan (25); an internal fan (26); and an inside air control system (60) including an exhaust passage (46a) which allows a space on a blowout side of the internal fan (26) in the internal storage space (S2) to communicate with the external storage space (S1), and controls composition of the inside air in the container (11). An external end of the exhaust passage (46a) is open on a suction side of the external fan (25) in the external storage space