To reduce exhaust gas and dark smoke from liquid fuel and to improve fuel firing efficiency by installing a simple apparatus.

This apparatus has the following structure: a composition prepared by adding lactic acid, U-PICA or the like to both fine particles obtained through burning ultra fine powder of 11 kinds of raw materials (e.g. diamond chips, chromium, titanium, etc.), and fine particles of 17 kinds of raw materials (e.g. gold, silver, nickel etc.), and by pressing and heating the mixture is shaped into a hemispheric body 4; perforating a bore in the center of the body 4 and burying the body 4 into punching metal 6; assembling a container 2 where two sheets of the punching metal 6 each having the hemispheric body 4 are placed at both sides and plural hemispheric bodies 4 are fixed between the sides; and liquid fuel is made to pass through the bores and on the outer surfaces of the bodies 4. When the apparatus is installed between a fuel tank and a carburetor, reduction in exhaust gas, dark smoke and nitrogen oxides and improvement in fuel firing efficiency are effectively attained.