A refrigerating cycle system comprising: a compressor configured to compress a refrigerant; a condenser configured to condense compressed refrigerant discharged from the compressor; an expansion valve configured to expand the compressed refrigerant condensed by the condenser; an evaporator configured to vaporize the compressed refrigerant expanded by the expansion valve; and an accumulator (12, 12A) configured to, once a stored gas-liquid mixed refrigerant has returned from the evaporator to the compressor, separate the gas-liquid mixed refrigerant into a liquefied refrigerant and a vaporized refrigerant, and to make the compressor suck only the vaporized refrigerant, wherein the accumulator (12, 12A) includes: a pressure vessel; a refrigerant inflow section configured to allow the gas-liquid mixed refrigerant to flow into the pressure vessel; a refrigerant outflow section configured to allow the vaporized refrigerant to flow toward the compressor; and an electric heating element (23, 23A), characterized in that the electric heating element (23, 23A) is provided at a position of an allowable highest liquid level of the liquefied refrigerant in the pressure vessel, of the pressure vessel, and in that the refrigerating cycle system further comprises a controller configured to detect a change of a heating value of the electric heating element (23, 23A) by detecting a change of power consumption, and to perform protection operation for lowering the liquid level of the liquefied refrigerant in a case where the power consumption reaches a predetermined threshold value. a compressor configured to compress a refrigerant; a condenser configured to condense compressed refrigerant discharged from the compressor; an expansion valve configured to expand the compressed refrigerant condensed by the condenser; an evaporator configured to vaporize the compressed refrigerant expanded by the expansion valve; and an accumulator (12, 12A) configured to, once a stored gas-liquid mixed refrigerant has returned from the evaporator to the compressor, separate the gas-liquid mixed refrigerant into a liquefied refrigerant and a vaporized refrigerant, and to make the compressor suck only the vaporized refrigerant, wherein the accumulator (12, 12A) includes: a pressure vessel; a refrigerant inflow section configured to allow the gas-liquid mixed refrigerant to flow into the pressure vessel; a refrigerant outflow section configured to allow the vaporized refrigerant to flow toward the compressor; and an electric heating element (23, 23A), characterized in that the electric heating element (23, 23A) is provided at a position of an allowable highest liquid level of the liquefied refrigerant in the pressure vessel, of the pressure vessel, and a pressure vessel; a refrigerant inflow section configured to allow the gas-liquid mixed refrigerant to flow into the pressure vessel; a refrigerant outflow section configured to allow the vaporized refrigerant to flow toward the compressor; and an electric heating element (23, 23A), characterized in that the electric heating element (23, 23A) is provided at a position of an allowable highest liquid level of the liquefied refrigerant in the pressure vessel, of the pressure vessel, and in that the refrigerating cycle system further comprises a controller configured to detect a change of a heating value of the electric heating element (23, 23A) by detecting a change of power consumption, and to perform protection operation for lowering the liquid level of the liquefied refrigerant in a case where the power consumption reaches a predetermined threshold value.