NOVELTY - Sodium methoxide or potassium methoxide is reacted with waste vegetable oil. The viscosity of reaction solution (21) is measured, and the reaction is terminated when the viscosity is less than a predetermined value. Glycerol and modified fuel in solution are separated, and glycerol is ejected and modified fuel is removed. Fuel is neutralized and washed, and moisture content and impurities in fuel are removed, to obtain a modified fuel.    USE - For manufacture of modified fuel, used for micro gas turbine and diesel engine, using waste vegetable oil including edible oil used by home and food service industry.    ADVANTAGE - The novel modified fuel is manufactured quickly using a simple apparatus. The reaction is performed quickly by measuring the value of viscosity of reaction solution. The moisture content is removed quickly and reliably by judging the completion time of moisture content removal. The separation of glycerol and modified fuel is performed quickly.    DETAILED DESCRIPTION - Sodium or potassium methoxide, obtained by reacting sodium hydroxide or potassium hydroxide with methanol, is reacted with waste vegetable oil. The viscosity of reaction solution is measured, and the reaction is terminated when the viscosity is less than a predetermined value. Glycerol and modified fuel in the solution are separated. The glycerol is ejected and modified fuel is removed. The modified fuel is neutralized and washed, and moisture content and impurities contained in fuel are removed, to obtain a modified fuel.    An INDEPENDENT CLAIM is included for waste vegetable oil reformer having a reaction portion, an isolation portion, an extraction portion, an impurity removal portion, a washing portion, a moisture content removal portion and a viscosity meter. Sodium or potassium methoxide is reacted with waste vegetable oil, in reaction portion. The viscosity of resulting solution is measured using viscosity meter (25). Glycerol and modified fuel in the solution are separated in isolation portion. Glycerol is ejected and modified fuel is removed in extraction portion. The modified fuel is neutralized and washed in washing portion. Impurities contained in neutralized modified fuel is coagulated and sedimented, and removed in impurity removal portion. Moisture content contained in fuel is removed in moisture content removal portion.    DESCRIPTION OF DRAWING(S) - The figure shows the above modified fuel manufacturing process.    reaction container (20)    reaction solution (21)    motor (22)    shaft (23)    viscosity meter (25)    determination portion (26)    stop-signal production portion (27)