A refrigeration apparatus (100, 500) comprising: a first cycle (RC, 510) including a first compressor (11, 511), a first radiator (14, 512), a first expansion mechanism (31, 513), and a first heat absorber (RP, 514) that are arranged in such a manner as to be connected to the first cycle, a first refrigerant circulating through the first cycle; and a second cycle (HC, 520) including a second radiator (HP, 523) and a second heat absorber (60, 527) that are arranged in such a manner as to be connected to the second cycle, a second refrigerant circulating through the second cycle, wherein the first heat absorber (RP, 514) and the second radiator (HP, 523) constitute a heat exchanger (33, 531) in which heat is exchanged between the first refrigerant flowing through the first heat absorber (RP, 514) and the second refrigerant flowing through the second radiator (HP, 523), and at least one of the first refrigerant and the second refrigerant is a refrigerant mixture comprising trans-1,2-difluoroethylene (HFO-1132), difluoromethane, and 2,3,3,3-tetrafluoro-1-propene (R1234yf), characterized in that when the mass% of HFO-1132, R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132, R32, and R1234yf is 100 mass% are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points: point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments; the line segment ON is represented by coordinates (0.0072y 2 -0.6701y+37.512, y, -0.0072y 2 -0.3299y+62.488); the line segment NU is represented by coordinates (0.0083y 2 -1.7403y+56.635, y, -0.0083y 2 +0.7403y+43.365); and the line segment UO is a straight line, and the refrigerant comprises HFO-1132, R32, and R1234yf in a total amount of 99.5 mass% or more based on the entire refrigerant. a first cycle (RC, 510) including a first compressor (11, 511), a first radiator (14, 512), a first expansion mechanism (31, 513), and a first heat absorber (RP, 514) that are arranged in such a manner as to be connected to the first cycle, a first refrigerant circulating through the first cycle; and a second cycle (HC, 520) including a second radiator (HP, 523) and a second heat absorber (60, 527) that are arranged in such a manner as to be connected to the second cycle, a second refrigerant circulating through the second cycle, wherein the first heat absorber (RP, 514) and the second radiator (HP, 523) constitute a heat exchanger (33, 531) in which heat is exchanged between the first refrigerant flowing through the first heat absorber (RP, 514) and the second refrigerant flowing through the second radiator (HP, 523), and at least one of the first refrigerant and the second refrigerant is a refrigerant mixture comprising trans-1,2-difluoroethylene (HFO-1132), difluoromethane, and 2,3,3,3-tetrafluoro-1-propene (R1234yf), characterized in that when the mass% of HFO-1132, R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132, R32, and R1234yf is 100 mass% are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points: point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments; the line segment ON is represented by coordinates (0.0072y 2 -0.6701y+37.512, y, -0.0072y 2 -0.3299y+62.488); the line segment NU is represented by coordinates (0.0083y 2 -1.7403y+56.635, y, -0.0083y 2 +0.7403y+43.365); and the line segment UO is a straight line, and point O (22.6, 36.8, 40.6), point N (27.7, 18.2, 54.1), and point U (3.9, 36.7, 59.4), or on these line segments; the line segment ON is represented by coordinates (0.0072y 2 -0.6701y+37.512, y, -0.0072y 2 -0.3299y+62.488); the line segment NU is represented by coordinates (0.0083y 2 -1.7403y+56.635, y, -0.0083y 2 +0.7403y+43.365); and the line segment UO is a straight line, and the line segment ON is represented by coordinates (0.0072y 2 -0.6701y+37.512, y, -0.0072y 2 -0.3299y+62.488); the line segment NU is represented by coordinates (0.0083y 2 -1.7403y+56.635, y, -0.0083y 2 +0.7403y+43.365); and the line segment UO is a straight line, and the refrigerant comprises HFO-1132, R32, and R1234yf in a total amount of 99.5 mass% or more based on the entire refrigerant.