Vapor jet refrigerating and heat pumping apparatus for a ship to be used for prevention of icing of the trap (54b), guardrail (54a), etc. in winter season and for air conditioning of cabins, etc in summer season. A refrigerant in a vapor generator (50) is boiled utilizing the waste heat of the propulsion and auxiliary machinery (56) and the generated vapor is introduced to the nozzle of an ejector (52) as the driving vapor. The driving vapor jetting from the nozzle induces the vapor in an refrigerant evaporator (14,51) connected to the induction zone of the same and the mixed vapor of the induced vapor and the driving vapor is introduced to a vapor carrying passage (60A) which carries the vapor to desired parts (41,54) or a condensing space (42) formed at a part of the ship to condense the vapor. The condensed refrigerant is returned to the evaporator (14,51) and the vapor generator (50). A superheater (10) is disposed between the upper space in the vapor generator (50) and the outlet side of the ejector (52), and a preheater (11) on the entrance passage of the condensed liquid refrigerant to the vapor generator (50), and waste heat of relative lower temperature is introduced to the preheater (11) and that of relative higher temperature to the superheater (10), selecting plural waste heat of different temperature from the waste heat of the propulsion and auxiliary machinery (56) of the ship.