PURPOSE: To reduce heating quantity of heat for vaporizing and heating methanol and improve the overall efficiency of an engine by using quantity of heat kept in reaction formed gas for forming DME from methanol for vaporizing and heating the methanol.

CONSTITUTION: In a diesel engine using methanol for fuel, the methanol is adapted to make contact with a catalyst to form dimethylether(DME). High temperature gas formed after the catalyst reaction for forming the DME is introduced to the outer periphery of a methanol vaporizing part to be subjected to the heat exchange and utilized for vaporizing and heating the methanol. Further, a DME generator is composed of a methanol heating-vaporizing part 5 having a methanol injecting nozzle 4 and a catalyst reaction part 6 to be provided in an exhaust gas path chamber 7. Thus, a heat source needed to ignite the methanol in the diesel engine using the methanol for fuel can be reduced.