A heat pump type hot water supply apparatus comprising: a main circuit in which a compressor, a flow switching device, a water heat exchanger, an expansion device and an evaporator are connected by pipes, the apparatus performing a reverse defrosting operation in which a refrigerant discharged from the compressor is made to flow into the evaporator by switching a flow of the refrigerant by the flow switching device, characterized in that the apparatus further comprises: an outside air temperature sensor which detects an outside air temperature of the evaporator, a shell temperature sensor which detects a shell temperature of the compressor, a low pressure sensor which detects a low pressure of the refrigerant to be suctioned into the compressor, and a controller which controls the heat pump type hot water supply apparatus, wherein the controller is configured to: perform the reverse defrosting operation in which the refrigerant discharged from the compressor is conducted to passes other than a pass located at a lower portion of the evaporator, start, when the outside air temperature is a predetermined temperature or less after completion of the reverse defrosting operation, a hot gas defrosting operation in which the refrigerant discharged from the compressor is branched off between the compressor and the flow switching device, and is conducted to the pass located at the lower portion of the evaporator such that the refrigerant flows in parallel to the water heat exchanger, and complete the hot gas defrosting operation, when the predetermined time has not elapsed and a difference between the shell temperature and a low pressure saturation temperature converted from the low pressure becomes a predetermined value or less after the start of the hot gas defrosting operation. an outside air temperature sensor which detects an outside air temperature of the evaporator, a shell temperature sensor which detects a shell temperature of the compressor, a low pressure sensor which detects a low pressure of the refrigerant to be suctioned into the compressor, and a controller which controls the heat pump type hot water supply apparatus, wherein the controller is configured to: perform the reverse defrosting operation in which the refrigerant discharged from the compressor is conducted to passes other than a pass located at a lower portion of the evaporator, start, when the outside air temperature is a predetermined temperature or less after completion of the reverse defrosting operation, a hot gas defrosting operation in which the refrigerant discharged from the compressor is branched off between the compressor and the flow switching device, and is conducted to the pass located at the lower portion of the evaporator such that the refrigerant flows in parallel to the water heat exchanger, and complete the hot gas defrosting operation, when the predetermined time has not elapsed and a difference between the shell temperature and a low pressure saturation temperature converted from the low pressure becomes a predetermined value or less after the start of the hot gas defrosting operation. perform the reverse defrosting operation in which the refrigerant discharged from the compressor is conducted to passes other than a pass located at a lower portion of the evaporator, start, when the outside air temperature is a predetermined temperature or less after completion of the reverse defrosting operation, a hot gas defrosting operation in which the refrigerant discharged from the compressor is branched off between the compressor and the flow switching device, and is conducted to the pass located at the lower portion of the evaporator such that the refrigerant flows in parallel to the water heat exchanger, and complete the hot gas defrosting operation, when the predetermined time has not elapsed and a difference between the shell temperature and a low pressure saturation temperature converted from the low pressure becomes a predetermined value or less after the start of the hot gas defrosting operation.