A heat pump apparatus that can easily prevent noise generated during partial-load operation is provided. The heat pump apparatus includes a centrifugal compressor (6) configured to compress a refrigerant; a condenser (2) configured to condense the compressed refrigerant; an expansion valve (3) configured to adiabatically expand the condensed refrigerant; an evaporator (4) configured to vaporize the adiabatically-expanded refrigerant; a container (5) into which the vaporized refrigerant flows and from which the refrigerant that flowed in flows out to the centrifugal compressor (6); a sound-insulating member (51) configured to cover the container (5) and prevent sound generated inside the container (5) from leaking outside; a bypass channel (8) configured to guide part of the refrigerant from an area between the centrifugal compressor (6) and the condenser (2) to the container (5); and a flow control valve (9) configured to control the flow rate of the refrigerant flowing through the bypass channel (8).
