A heat pump device can discharge air in a heat medium circuit regardless of the height positions of two bodies of the heat pump device and prevents refrigerant outflow when the refrigerant enters the heat medium circuit in the liquid heat exchanger. A pump causes the liquid heat medium to flow in a predetermined circulatory direction in a heat medium pipe, and a liquid heat exchanger, a first air vent valve and a second air vent valve are arranged in this order along a circulatory direction.