The invention discloses a mechanical arm of a bulb-paperboard feeding device, and belongs to the field of auto spare parts. The mechanical arm comprises a frame, side-edge upper shaft bases, side-edge upper grippers, springs, lower end grippers, lower end shaft bases, side-edge lower grippers and side-edge lower shaft bases. The frame is a rectangular frame made from a thin steel plate; the two side-edge upper shaft bases are installed at the upper ends of the two side edges of the frame respectively; the two side-edge upper grippers are installed on the two side-edge upper shaft bases respectively; the four springs are installed in the middles of the two side edges and the middles of the two ends of the frame respectively; the two lower end grippers are installed on the two lower end shaft bases respectively; the two side-edge lower shaft bases are installed at the lower portions of the two side edges of the frame respectively. The mechanical arm has the advantages that the function of the mechanical arm of the bulb-paperboard feeding device of an automatic middle-lamp packaging machine can be achieved, automatic packaging of automobile middle lamps is achieved accordingly, labor intensity is reduced, and working efficiency is improved.