A refrigeration apparatus configured to cool a refrigerant by heat exchange between the refrigerant and water, the refrigeration apparatus comprising: a low-stage compression mechanism; a high-stage compression mechanism; an expansion mechanism; an intercooler configured to cool the refrigerant discharged from the low-stage compression mechanism; a main gas cooler configured to cool the refrigerant discharged from the high-stage compression mechanism; an auxiliary gas cooler configured to cool the refrigerant that has passed through the main gas cooler; a water pipe constituting a flow passage of water for cooling the refrigerant, the water pipe including: a first water pipe; a first branch point where the first water pipe branches midway; a first merging point; a second water pipe connecting the first branch point and the first merging point through the auxiliary gas cooler; a third water pipe connecting the first branch point and the first merging point through the intercooler without merging with the second water pipe; a fourth water pipe connecting the first merging point and the main gas cooler; and a hot water supply pipe connecting the main gas cooler and a hot water supply destination; and a water feeding mechanism disposed in a midway part of the water pipe, a control unit configured to control the water feeding mechanism; and an outlet-side water temperature sensor disposed on the hot water supply pipe, the outlet-side water temperature sensor being configured to detect an outlet-side water temperature of the main gas cooler, wherein the water feeding mechanism controls a flow rate of the water pipe, and the control unit controls the water feeding mechanism on the basis of a detection value of the outlet-side water temperature sensor, an inlet-side water temperature sensor disposed on the first water pipe, the inlet-side water temperature sensor being configured to detect a temperature of water entering the auxiliary gas cooler and the intercooler; characterized by further comprising: a refrigerant temperature sensor configured to measure a temperature of the refrigerant that has passed through the auxiliary gas cooler; a drain pipe connected to the fourth water pipe; and a first flow regulating mechanism configured to regulate a flow rate of water flowing to the main gas cooler and the drain pipe, wherein the control unit is configured to control the first flow regulating mechanism. a low-stage compression mechanism; a high-stage compression mechanism; an expansion mechanism; an intercooler configured to cool the refrigerant discharged from the low-stage compression mechanism; a main gas cooler configured to cool the refrigerant discharged from the high-stage compression mechanism; an auxiliary gas cooler configured to cool the refrigerant that has passed through the main gas cooler; a water pipe constituting a flow passage of water for cooling the refrigerant, the water pipe including: a first water pipe; a first branch point where the first water pipe branches midway; a first merging point; a second water pipe connecting the first branch point and the first merging point through the auxiliary gas cooler; a third water pipe connecting the first branch point and the first merging point through the intercooler without merging with the second water pipe; a fourth water pipe connecting the first merging point and the main gas cooler; and a hot water supply pipe connecting the main gas cooler and a hot water supply destination; and a first water pipe; a first branch point where the first water pipe branches midway; a first merging point; a second water pipe connecting the first branch point and the first merging point through the auxiliary gas cooler; a third water pipe connecting the first branch point and the first merging point through the intercooler without merging with the second water pipe; a fourth water pipe connecting the first merging point and the main gas cooler; and a hot water supply pipe connecting the main gas cooler and a hot water supply destination; and a water feeding mechanism disposed in a midway part of the water pipe, a control unit configured to control the water feeding mechanism; and an outlet-side water temperature sensor disposed on the hot water supply pipe, the outlet-side water temperature sensor being configured to detect an outlet-side water temperature of the main gas cooler, wherein the water feeding mechanism controls a flow rate of the water pipe, and the control unit controls the water feeding mechanism on the basis of a detection value of the outlet-side water temperature sensor, an inlet-side water temperature sensor disposed on the first water pipe, the inlet-side water temperature sensor being configured to detect a temperature of water entering the auxiliary gas cooler and the intercooler; characterized by further comprising: a refrigerant temperature sensor configured to measure a temperature of the refrigerant that has passed through the auxiliary gas cooler; a drain pipe connected to the fourth water pipe; and a first flow regulating mechanism configured to regulate a flow rate of water flowing to the main gas cooler and the drain pipe, wherein the control unit is configured to control the first flow regulating mechanism. a refrigerant temperature sensor configured to measure a temperature of the refrigerant that has passed through the auxiliary gas cooler; a drain pipe connected to the fourth water pipe; and a first flow regulating mechanism configured to regulate a flow rate of water flowing to the main gas cooler and the drain pipe, wherein the control unit is configured to control the first flow regulating mechanism.