A mixing portion that mixes an injection refrigerant and a suction refrigerant is formed in a range of an internal space of a heating-side body portion of a heating-side ejector from a refrigerant injection port of a heating-side nozzle portion to an inlet of a heating-side diffuser. Further, the mixing portion is formed in a shape that gradually decreases a refrigerant passage area toward a downstream side of a refrigerant flow, and a refrigerant passage area of the inlet of the heating-side diffuser is set smaller than that of the refrigerant injection port. Thus, the flow velocity of the mixed refrigerant is decelerated to a value lower than a two phase sound velocity within the mixing portion, thereby suppressing occurrence of shock wave in the heating-side diffuser and stabilizing the pressure increasing performance in the heating-side diffuser.