NOVELTY - The apparatus has a reaction tank (4) for irradiating a microwave and making oil, fat and alcohol react in presence of a solid alkali catalyst, and a splitter (5) for separating unreacted alcohol from the reaction product generated in the reaction tank. The splitter continuously performs the separation process of reaction product generated within the reaction tank and the unreacted alcohol.    USE - Manufacturing apparatus of biodiesel fuel.    ADVANTAGE - Since microwave irradiation is carried out for the treatment of oil, fat and alcohol in the presence of solid alkali catalyst, the reaction time of oil, fat and alcohol can be shortened remarkably. A liquid reaction product, unreacted alcohol and solid alkali catalyst can be easily filtered by the filter. The need for separately implementing the neutralization process using the acid can be avoided. The holdup of the reaction product and the unreacted alcohol inside the tank can be controlled effectively according to a transfer speed hence the volume of the tank can be reduced. Since unreacted alcohol is effectively separated from the mixture of the biodiesel fuel which is a reaction main product of oil, fat and alcohol, and the glycerol as a reaction by-product, the biodiesel fuel can be more suitably purified in the latter stage. The continuous supply and recycling of oil, fat and alcohol can be performed more efficiently.    DETAILED DESCRIPTION - A return line returns the separated unreacted alcohol to the reaction tank or former stage side, and a pipe (12) mounted between the reaction tank and the splitter transfers the reaction product and the unreacted alcohol to the splitter from the reaction tank. A filter (16) carries out the filtration process of the solid alkali catalyst in the tank, being carelessly transferred to the splitter side. A microwave heater carries out the separation process of the unreacted alcohol from the reaction product inside the splitter, by the microwave exposure process. An INDEPENDENT CLAIM is included for manufacturing method of biodiesel fuel.    DESCRIPTION OF DRAWING(S) - The drawing shows the schematic front view of the reaction tank and splitter in the manufacturing apparatus.    Reaction tank (4)    Splitter (5)    Pipe (12)    Connecting pipe (15)    Filter (16)