To provide a combustion method of an emulsion fuel by an internal combustion engine which can remarkably reduce a petroleum fuel and reduce an exhaust gas by high combustion of the emulsion fuel of the petroleum fuel and water.

In a holding plate, a large number of micronizing dispersion mixing protrusions for micronizing the petroleum and water sprayed to the inside of a cylindrical outer wrapping body at proper intervals by colliding, disturbing and crushing them and by uniformly dispersing and mixing them, is formed. The emulsion fuel is burnt by an injector in which a micronizing dispersion mixing module in which the holding plates are laminated with a necessary gap therebetween is arranged in the lower part of the needle valve of the injector.