A container refrigerator operating with a generator connected thereto as its power supply and generating equivalent negative-phase-sequence current during its operation, the refrigerator comprising: a first calculator which calculates a permissible equivalent negative-phase-sequence current (I tg) of the generator connected; a second calculator which calculates the equivalent negative-phase-sequence current (I t) generated during the operation; a restrictor which restricts the equivalent negative-phase-sequence current (I t) generated to the permissible equivalent negative-phase-sequence current (I tg) of the generator or less if the equivalent negative-phase-sequence current (I t) generated that has been calculated exceeds the permissible equivalent negative-phase-sequence current (I tg) of the generator. a power converter which converts power supplied from the generator and supplies the converted power to a predetermined component device; and a controller which controls the frequency of the power converted by the power converter, wherein the restrictor controls the controller to lower the frequency of the power converted by the power converter if the equivalent negative-phase-sequence current (I t) generated that has been calculated exceeds the permissible equivalent negative-phase-sequence current (I tg) of the generator; wherein the second calculator calculates a power to drive the power converter by subtracting a power to drive a component device (CFM, EFM) generating no harmonics from a power to drive the container refrigerator, and also calculates, based on the power (kWI) to drive the power converter that has been calculated, the equivalent negative-phase-sequence current (I t) generated. a first calculator which calculates a permissible equivalent negative-phase-sequence current (I tg) of the generator connected; a second calculator which calculates the equivalent negative-phase-sequence current (I t) generated during the operation; a restrictor which restricts the equivalent negative-phase-sequence current (I t) generated to the permissible equivalent negative-phase-sequence current (I tg) of the generator or less if the equivalent negative-phase-sequence current (I t) generated that has been calculated exceeds the permissible equivalent negative-phase-sequence current (I tg) of the generator. a power converter which converts power supplied from the generator and supplies the converted power to a predetermined component device; and a controller which controls the frequency of the power converted by the power converter, wherein the restrictor controls the controller to lower the frequency of the power converted by the power converter if the equivalent negative-phase-sequence current (I t) generated that has been calculated exceeds the permissible equivalent negative-phase-sequence current (I tg) of the generator; wherein the second calculator calculates a power to drive the power converter by subtracting a power to drive a component device (CFM, EFM) generating no harmonics from a power to drive the container refrigerator, and also calculates, based on the power (kWI) to drive the power converter that has been calculated, the equivalent negative-phase-sequence current (I t) generated.