A room-warming/cooling and hot-water supplying heat-pump apparatus comprises a refrigerant circuit provided with a compressor, a four-way valve for switching room warming and cooling operations, a room side heat exchanger, a reversible flow type expansion device and an outdoor side heat exchanger, wherein a first switching means is connected to the outlet side of the compressor; a first branch of the switching means is connected to the four-way valve and a second branch of the first switching means is connected to one end of a heating coil in a hot water tank; the other end of the heating coil extends out of the hot water tank and has a branched part. A pipeline including the branched part has both ends connected to the refrigerant circuit at both sides of the expansion device in which at least one valve means is provided in the pipeline including the branched part and the first switching means and the valve means are controlled by a control device.