PURPOSE: To provide a fuel recovering device capable of obviating or reducing supply of water as a part of fuel and greatly simplifying the control of fuel in vehicles.

CONSTITUTION: A condenser 33 serving as an evaporator of a refrigerating cycle is provided in the exhaust path of an emulsion fuel engine for which emulsion fuel is formed by mixing light oil in a first tank and water in a second tank 11 by means of a fuel force-feeding/mixing pump 14 and it is fed into an injection nozzle 8 by injection pressure of an injection pump and then it is injected into a combustion chamber. Exhaust gas is cooled by the condenser 33. Steam is included in exhaust gas and condensed by cooling by the condenser 33. The condensed water is separated and recovered by a cyclone 4 and fed into the second tank 11.