It is a new fillet-forming and end reducing device with engaging gear assembly used for machining reducing end with taper, which has advantages such as beautiful figure, mean reducing size and high strength for the formed product, and for the device itself, the advanced property embodies that different diameters outer-barrels are available to be machined by one device, various material including SS plate, sheet zinc with aluminum plated, color plate etc being machined without mould replacement, which shall reduce the production costs greatly.