Disclosed is a high speed defrosting heat pump having a closed refrigerant circulation loop including a four-way valve so as to conduct cooling and heating operations by switching a refrigerant-circulating direction by means of the four-way valve. A three-way valve is disposed on a refrigerant pipe connected between a compressor and the four-way valve, and a bypass pipe is branched off from the three-way valve in such a manner as to be connected to a refrigerant pipe connected between an expansion valve and a exterior heat exchanger, such that the hot gas discharged from the compressor is introduced to the exterior heat exchanger via the bypass tube by the control of the three-way valve.