Disclosed is a defrosting apparatus that comprises: a heating unit provided below an evaporator; and a heat pipe connected to the inlet and outlet of the heating unit and having at least a part disposed adjacent to a cooling pipe of the evaporator such that heat is radiated toward the cooling pipe of the evaporator by a high-temperature working liquid that is heated and delivered by the heating unit, wherein the heating unit comprises: a heater case extending along one direction and disposed along the left and right direction of the evaporator, the inlet and outlet being provided on opposite sides of the heater case; and a heater that comprises an active heating part accommodated in the heater case to actively generate heat to heat the working liquid and a passive heating part extending from the active heating part and heated to a lower temperature than that of the active heating part, wherein the inlet is formed in a position beyond the active heating part to prevent the working liquid returning to the heating unit after travelling along the heat pipe from directly flowing into the active heating part.