The invention discloses a tear line machining device. The tear line machining device comprises a frame, a feeding device, a tear line machining device, a guide roller and a collecting device. The frame comprises a fixed rack and a frame plate, wherein the fixed rack is fixed on the ground, the frame plate is arranged on the fixed rack, the frame plate is perpendicular to the horizontal ground, the guide roller which guides a thin film to move is perpendicularly arranged on the frame plate, the guide roller is a driving guide roller, a driving motor is arranged at one end of the guide roller, the tear line machining device is arranged on the frame plate, and the feeding device and the collecting device are arranged on the frame. The tear line machining device disclosed by the invention is simple in structure and convenient to use, and can be used for efficiently machining a tear line.