A device for filtration of gas-oil intended to supply a diesel engine comprises an electric heating unit which includes a casing internally defining a chamber for heating the gas-oil to be filtered, a filtration unit which includes a casing internally defining a chamber for filtration of the heated gas-oil, means for connecting the heating and filtration chambers and means for assembly of the casings of the heating and filtration units. The connection means include means for directly and tightly connecting the chambers of the said units. The assembly means include means for detachable fixing of the casing of one of the heating and filtration units to the casing of the other of the said units, and means for retention in translation of one of the units relative to the other.