The invention discloses a fully-automatic synthesis device for continuously producing a whisker-shaped carbon nano tube. The fully-automatic synthesis device is characterized by comprising an atomizer (1), a scraping ring (2), a furnace body (3), a heating device (4), an upper sealing valve (5), a first valve (6), a second valve (7), a lower sealing valve (8), a third valve (9), a fourth valve (10), a charging skip (11), a fifth valve (12), a connecting bin (13), a vacuum bin (14), a sixth valve (15), a cover board (16), a pneumatic conveying system (17), a vacuum packaging system (18), a vacuum pump (19) and an exhaust pipe (20). The fully-automatic synthesis device can be used for producing a very straight whisker-shaped carbon nano tube to ensure that the whisker-shaped carbon nano tube is dispersed easily, thereby opening up a wide rod for the industrial application of the whisker-shaped carbon nano tube.