A refrigeration apparatus, comprising: a utilization unit having a utilization heat exchanger, and a heat source unit, wherein the heat source unit comprises: a heat source circuit including a compression element, a heat source heat exchanger, a subcooling heat exchanger, and a switching mechanism, the heat source unit being connected to the utilization unit having the utilization heat exchanger to constitute a refrigerant circuit that performs a refrigeration cycle, wherein the switching mechanism is configured to switch the refrigeration cycle between a first refrigeration cycle in which the heat source heat exchanger serves as a radiator and the utilization heat exchanger serves as an evaporator, and a second refrigeration cycle in which the utilization heat exchanger serves as a radiator and the heat source heat exchanger serves as an evaporator, the subcooling heat exchanger has a first channel connected to a middle portion of a liquid pipe (32, 33) through which a liquid refrigerant in the heat source circuit flows, and a second channel through which a heating medium for cooling the refrigerant in the first channel flows, the heat source unit further comprises a regulation mechanism including an expansion valve connected to an upstream side of the second channel and a control unit, characterized in that the control unit is configured to control an opening degree of the expansion valve so that the cooling capability is reduced in a first operation of reducing a capability of the second channel of cooling the refrigerant in the first channel before switching from the first refrigeration cycle to the second refrigeration cycle. a utilization unit having a utilization heat exchanger, and a heat source unit, wherein the heat source unit comprises: a heat source circuit including a compression element, a heat source heat exchanger, a subcooling heat exchanger, and a switching mechanism, the heat source unit being connected to the utilization unit having the utilization heat exchanger to constitute a refrigerant circuit that performs a refrigeration cycle, wherein the switching mechanism is configured to switch the refrigeration cycle between a first refrigeration cycle in which the heat source heat exchanger serves as a radiator and the utilization heat exchanger serves as an evaporator, and a second refrigeration cycle in which the utilization heat exchanger serves as a radiator and the heat source heat exchanger serves as an evaporator, the subcooling heat exchanger has a first channel connected to a middle portion of a liquid pipe (32, 33) through which a liquid refrigerant in the heat source circuit flows, and a second channel through which a heating medium for cooling the refrigerant in the first channel flows, the heat source unit further comprises a regulation mechanism including an expansion valve connected to an upstream side of the second channel and a control unit, a heat source circuit including a compression element, a heat source heat exchanger, a subcooling heat exchanger, and a switching mechanism, the heat source unit being connected to the utilization unit having the utilization heat exchanger to constitute a refrigerant circuit that performs a refrigeration cycle, wherein the switching mechanism is configured to switch the refrigeration cycle between a first refrigeration cycle in which the heat source heat exchanger serves as a radiator and the utilization heat exchanger serves as an evaporator, and a second refrigeration cycle in which the utilization heat exchanger serves as a radiator and the heat source heat exchanger serves as an evaporator, a first refrigeration cycle in which the heat source heat exchanger serves as a radiator and the utilization heat exchanger serves as an evaporator, and a second refrigeration cycle in which the utilization heat exchanger serves as a radiator and the heat source heat exchanger serves as an evaporator, the subcooling heat exchanger has a first channel connected to a middle portion of a liquid pipe (32, 33) through which a liquid refrigerant in the heat source circuit flows, and a second channel through which a heating medium for cooling the refrigerant in the first channel flows, the heat source unit further comprises a regulation mechanism including an expansion valve connected to an upstream side of the second channel and a control unit,