A hydrogen cooling apparatus configured to cool hydrogen transported in a hydrogen passage; the hydrogen cooling apparatus comprising: a first coolant passage through which a first coolant circulates; a water-cooled refrigerator unit disposed on a part of the first coolant passage to enable cooling of the first coolant; a second coolant passage through which a second coolant flows; a first heat exchanger enabling cooling of the second coolant by the first coolant, between another part of the first coolant passage and a part of the second coolant passage; a second heat exchanger enabling cooling of the hydrogen by the second coolant, between another part of the second coolant passage and a part of the hydrogen passage; wherein: the first coolant is flon; the second coolant is potassium formate solution; the second coolant passage is composed of a first half passage including the part of the second coolant passage where heat is exchanged between the part of the second coolant passage and the other part of the first coolant passage by the first heat exchanger, and a second half passage including the other part of the second coolant passage where heat is exchanged between the other part of the second coolant passage and the part of the hydrogen passage by the second heat exchanger; a flow rate of the second coolant flowing through the second half passage of the second coolant passage is between 135 L/min and 165 L/min at a flow pressure of 0.3 Mpa; the hydrogen is cooled down to a temperature range of between -43°C and -20°C by the second heat exchanger; the hydrogen is cooled to a temperature within an error span between +2°C and -3°C with respect to a set temperature within the temperature range of between -43°C and - 20°C by the second heat exchanger; a hydrogen cooling power for cooling hydrogen to -40°C is between 13.5 kW and 16. kW; the hydrogen passage has an outlet port from which the hydrogen having been cooled by the second heat exchanger is discharged; and a flow rate of the hydrogen discharged from the outlet port is between 4.5 kg/3 minutes and 5.5 kg/3 minutes. a first coolant passage through which a first coolant circulates; a water-cooled refrigerator unit disposed on a part of the first coolant passage to enable cooling of the first coolant; a second coolant passage through which a second coolant flows; a first heat exchanger enabling cooling of the second coolant by the first coolant, between another part of the first coolant passage and a part of the second coolant passage; a second heat exchanger enabling cooling of the hydrogen by the second coolant, between another part of the second coolant passage and a part of the hydrogen passage; wherein: the first coolant is flon; the second coolant is potassium formate solution; the second coolant passage is composed of a first half passage including the part of the second coolant passage where heat is exchanged between the part of the second coolant passage and the other part of the first coolant passage by the first heat exchanger, and a second half passage including the other part of the second coolant passage where heat is exchanged between the other part of the second coolant passage and the part of the hydrogen passage by the second heat exchanger; a flow rate of the second coolant flowing through the second half passage of the second coolant passage is between 135 L/min and 165 L/min at a flow pressure of 0.3 Mpa; the hydrogen is cooled down to a temperature range of between -43°C and -20°C by the second heat exchanger; the hydrogen is cooled to a temperature within an error span between +2°C and -3°C with respect to a set temperature within the temperature range of between -43°C and - 20°C by the second heat exchanger; a hydrogen cooling power for cooling hydrogen to -40°C is between 13.5 kW and 16. kW; the hydrogen passage has an outlet port from which the hydrogen having been cooled by the second heat exchanger is discharged; and a flow rate of the hydrogen discharged from the outlet port is between 4.5 kg/3 minutes and 5.5 kg/3 minutes. the first coolant is flon; the second coolant is potassium formate solution; the second coolant passage is composed of a first half passage including the part of the second coolant passage where heat is exchanged between the part of the second coolant passage and the other part of the first coolant passage by the first heat exchanger, and a second half passage including the other part of the second coolant passage where heat is exchanged between the other part of the second coolant passage and the part of the hydrogen passage by the second heat exchanger; a flow rate of the second coolant flowing through the second half passage of the second coolant passage is between 135 L/min and 165 L/min at a flow pressure of 0.3 Mpa; the hydrogen is cooled down to a temperature range of between -43°C and -20°C by the second heat exchanger; the hydrogen is cooled to a temperature within an error span between +2°C and -3°C with respect to a set temperature within the temperature range of between -43°C and - 20°C by the second heat exchanger; a hydrogen cooling power for cooling hydrogen to -40°C is between 13.5 kW and 16. kW; the hydrogen passage has an outlet port from which the hydrogen having been cooled by the second heat exchanger is discharged; and a flow rate of the hydrogen discharged from the outlet port is between 4.5 kg/3 minutes and 5.5 kg/3 minutes.