NOVELTY - Continuous biodiesel preparing device comprises a oil cylinder (1) connected with a metering pump (3); a low carbon alcohol vessel (2) connected with a metering pump (9); and outlet pipe lines of the metering pump. The metering pumps are converged and connected to an inlet of a reactor (5) by a passive mixer (4). The reactor is closely padded with foam metal (6). An electrical heating and controlling device (7) is fixed in outer surface of a foam metal padding reactor. A gathering device (8) is connected in an outlet of the reactor.    USE - Device for continuously preparing biodiesel (claimed).    ADVANTAGE - The use of the device provides preparation of the biodiesel with simple technique, low energy consumption, high efficiency, continuous operation and convenience for abundant production.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for continuously preparing biodiesel comprising:    (A) injecting oil in the passive mixer by the metering pump and low carbon alcohol solution dissolved with alkali catalyst in the passive mixer, where mol ratio of low carbon alcohol to oil is 3-15:1, and dosage of alkali catalyst is 0.5-2 wt.%;    (B) injecting mixed solution in the mixer to the reactor, where reaction time is 0.5-5 minutes;    (C) adjusting and keeping reaction temperature at 20-130 degrees C, where reaction materials are gotten into the gathering device by the outlet of the reactor; and    (D) collecting, separating, purifying reaction materials in the gathering device and obtaining biodiesel.    The alkali catalyst is sodium hydroxide, potassium hydroxide and sodium methoxide. The oil is vegetable oil or animal oil.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic view of the continuous biodiesel preparing device.    Grease cylinder (1)    Low carbon alcohol vessel (2)    Metering pump (3)    Passive mixer (4)    Reactor (5)    Foam metal (6)    Electrical heating and controlling device (7)    Gathering device (8)    Metering pump (9)