A refrigeration system comprising: a refrigerant circuit including a compressor, a heat-source heat exchanger connected to a discharge side of the compressor at one end thereof, a liquid pipe connected to the other end of the heat-source heat exchanger through a heat-source expansion valve, a plurality of heat exchangers (31, 41, 51, 92) connected in parallel to the liquid pipe at one ends thereof, a plurality of expansion valves (32, 42, 52, 93), each of which is provided on one end of the corresponding heat exchanger (31, 41, 51, 92) to adjust an amount of a refrigerant flowing to the corresponding heat exchanger (31, 41, 51, 92), and a switching mechanism (24, 25, SV) which switches a flow path of the refrigerant so that the other ends of the heat exchangers (31, 41, 51, 92) are connected to one of a suction side and a discharge side of the compressor, characterized in that the refrigeration system includes a high-pressure-side pressure difference detection means (Ps1, Ps3, Ts7) which is configured to detect an index of pressure difference between a high pressure refrigerant on the discharge side of the compressor and a refrigerant in the liquid pipe in concurrent operation of performing a refrigeration cycle in which the heat-source heat exchanger functions as a condenser, and simultaneously, at least one of the plurality of heat exchangers (31, 41, 51, 92) functions as a condenser, and at least one of the plurality of heat exchangers (31, 41, 51, 92) functions as an evaporator, and an expansion valve control means which is configured to adjust the degree of opening of the heat-source expansion valve in the concurrent operation so that a value detected by the high-pressure-side pressure difference detection means (Ps1, Ps3, Ts7) becomes larger than a predetermined value. a refrigerant circuit including a compressor, a heat-source heat exchanger connected to a discharge side of the compressor at one end thereof, a liquid pipe connected to the other end of the heat-source heat exchanger through a heat-source expansion valve, a plurality of heat exchangers (31, 41, 51, 92) connected in parallel to the liquid pipe at one ends thereof, a plurality of expansion valves (32, 42, 52, 93), each of which is provided on one end of the corresponding heat exchanger (31, 41, 51, 92) to adjust an amount of a refrigerant flowing to the corresponding heat exchanger (31, 41, 51, 92), and a switching mechanism (24, 25, SV) which switches a flow path of the refrigerant so that the other ends of the heat exchangers (31, 41, 51, 92) are connected to one of a suction side and a discharge side of the compressor, characterized in that the refrigeration system includes a high-pressure-side pressure difference detection means (Ps1, Ps3, Ts7) which is configured to detect an index of pressure difference between a high pressure refrigerant on the discharge side of the compressor and a refrigerant in the liquid pipe in concurrent operation of performing a refrigeration cycle in which the heat-source heat exchanger functions as a condenser, and simultaneously, at least one of the plurality of heat exchangers (31, 41, 51, 92) functions as a condenser, and at least one of the plurality of heat exchangers (31, 41, 51, 92) functions as an evaporator, and an expansion valve control means which is configured to adjust the degree of opening of the heat-source expansion valve in the concurrent operation so that a value detected by the high-pressure-side pressure difference detection means (Ps1, Ps3, Ts7) becomes larger than a predetermined value.