PURPOSE: To obtain a fuel mixer, short and miniaturized, by a method wherein air is passed through a multitude of parallel porous tubes, in which fuel is oozed out of the tubes through the tube walls thereof, to mix the fuel with air.

CONSTITUTION: Fuel, from a fuel supplying pipe 21, is oozed out of a porous wall 19 in a cylinder 20 and the fuel is mixed with air in the cylinder. Air, from the upper part of the mixer, is chocked by respective porous tubes 19 and is diffused at the downstream side whereby the fuel is mixed with air more smoothly. When a multitude of fine porous tubes are arranged in parallel, mixing may be effected sufficiently and the length of a fuel mixer in the direction of air stream may be shortened.