A torque estimating device of a compressor for an ejector-type refrigerant cycle device includes a high pressure detector disposed to detect a physical amount having a relation with a high-pressure side refrigerant pressure of a refrigerant cycle, an evaporation pressure detector disposed to detect a physical amount having a relation with a refrigerant evaporation pressure in a suction side evaporator, a pressurizing estimating portion for estimating a pressurizing amount in a pressure increasing portion of an ejector to be increased in accordance with an increase of a pressure difference between the high-pressure side refrigerant pressure and the refrigerant evaporation pressure, and a suction pressure estimating portion for estimating a suction refrigerant pressure of the compressor by using the pressurizing amount estimated by the pressurizing estimating portion. Thus, a drive torque of the compressor can be accurately estimated in the ejector-type refrigerant cycle device.