PURPOSE: To reduce noxious composition in exhaust gas by enabling a distribution type injection pump, mixer and others of supplying emulsion fuel of light oil fuel and alcohol fuel without the need of expensive emulsifier.

CONSTITUTION: A separation tank 8 is supplied via fuel flow passages 6 and 14 with light oil fuel and alcohol fuel, which are separated into two layers due to a difference between their specific gravities. The light oil fuel separated in the separation tank 8 is sucked into a chamber 238 via a filter 28 and a light oil sucking port 224 of a distribution type injection pump 22. Similarly, the alcohol fuel separated in the separation tank 8 is sucked into a chamber 238 via a pump 30 and a filter 32 and an alcohol sucking port 24. Those fuels are fed into a static mixer 36, mixed to be emulsified and injected from an injection nozzle 38.