A refrigeration cycle device comprising: a compressor configured to compress refrigerant; a high temperature side heat exchanger configured to exchange heat between the refrigerant compressed by the compressor and a heat medium; an expansion unit configured to expand the refrigerant having passed through the high temperature side heat exchanger; a low temperature side heat exchanger configured to exchange heat between the refrigerant having passed through the expansion unit and a fluid; a feeding unit configured to feed the fluid to the low temperature side heat exchanger; control means configured to control an operation of the feeding unit so that an actual operating state approaches a target operating state of a refrigeration cycle, high pressure side refrigerant pressure being refrigerant pressure after compression by the compressor, low pressure side refrigerant pressure being refrigerant pressure before compression by the compressor, the target operating state being an operating state in which the high pressure side refrigerant pressure is minimized when the low pressure side refrigerant pressure is changed with a refrigerant compressing capacity of the compressor kept constant; and pressure detection means (7, 8) for detecting the low pressure side refrigerant pressure and the high pressure side refrigerant pressure, wherein when the low pressure side refrigerant pressure is changed with the refrigerant compressing capacity of the compressor kept constant, there are a range of the low pressure side refrigerant pressure in which the high pressure side refrigerant pressure decreases with decreasing low pressure side refrigerant pressure, and a range of the low pressure side refrigerant pressure in which the high pressure side refrigerant pressure increases with decreasing low pressure side refrigerant pressure, and the high pressure side refrigerant pressure is minimized between the ranges, the refrigeration cycle device being characterized in that information on a plurality of target operating state line connecting points of the low pressure side refrigerant pressure and the high pressure side refrigerant pressure in a plurality of the target operating states that differ depending on the refrigerant compressing capacity of the compressor is stored in the control means, and that the control means is configured to determine whether to increase or reduce a flow rate of the fluid depending on which side of the target operating state line a point represented by current low pressure side refrigerant pressure and current high pressure side refrigerant pressure detected by the pressure detection means (7, 8) is located on. a compressor configured to compress refrigerant; a high temperature side heat exchanger configured to exchange heat between the refrigerant compressed by the compressor and a heat medium; an expansion unit configured to expand the refrigerant having passed through the high temperature side heat exchanger; a low temperature side heat exchanger configured to exchange heat between the refrigerant having passed through the expansion unit and a fluid; a feeding unit configured to feed the fluid to the low temperature side heat exchanger; control means configured to control an operation of the feeding unit so that an actual operating state approaches a target operating state of a refrigeration cycle, high pressure side refrigerant pressure being refrigerant pressure after compression by the compressor, low pressure side refrigerant pressure being refrigerant pressure before compression by the compressor, the target operating state being an operating state in which the high pressure side refrigerant pressure is minimized when the low pressure side refrigerant pressure is changed with a refrigerant compressing capacity of the compressor kept constant; and pressure detection means (7, 8) for detecting the low pressure side refrigerant pressure and the high pressure side refrigerant pressure, wherein when the low pressure side refrigerant pressure is changed with the refrigerant compressing capacity of the compressor kept constant, there are a range of the low pressure side refrigerant pressure in which the high pressure side refrigerant pressure decreases with decreasing low pressure side refrigerant pressure, and a range of the low pressure side refrigerant pressure in which the high pressure side refrigerant pressure increases with decreasing low pressure side refrigerant pressure, and the high pressure side refrigerant pressure is minimized between the ranges, the refrigeration cycle device being characterized in that information on a plurality of target operating state line connecting points of the low pressure side refrigerant pressure and the high pressure side refrigerant pressure in a plurality of the target operating states that differ depending on the refrigerant compressing capacity of the compressor is stored in the control means, and that the control means is configured to determine whether to increase or reduce a flow rate of the fluid depending on which side of the target operating state line a point represented by current low pressure side refrigerant pressure and current high pressure side refrigerant pressure detected by the pressure detection means (7, 8) is located on.