The invention discloses a gear positioning device and a processing device thereof. A bottom plate is included, the bottom plate is provided with a hole groove, L-shaped positioning plates are symmetrically arranged at the positions, on the two sides of the hole groove, of the bottom plate, L-shaped suction pipes are arranged in the L-shaped positioning plates, and the ends, far away from a horn opening, of the L-shaped suction pipes are inserted into a slag gathering bottle; grooves are formed in the sides, close to the bottom plate, of the L-shaped positioning plates, and a first switch assembly and a second switch assembly are arranged in the grooves in the two sides; a positioning rotary motor and a micro suction fan are electrically connected to the first switch assembly; and a drilling motor is fixedly arranged on the side, far away from a telescopic cylinder, of a flat plate, and a drill rod is fixedly arranged at the output end of the drilling motor. By means of the gear positioning device, gears with different thicknesses can be accurately clamped, and debris and slag can be absorbed in time during processing. The invention also discloses the processing device including anabove-mentioned box structure, the automation degree of the device is high, and the processing efficiency is effectively improved.