The invention discloses a hemming device for a plate-shaped workpiece, which comprises an operating table, a top plate, a cylinder one, an adjustment plate, a pressure plate, a cylinder two, a push block, a fixed block, a hemming wheel, an auxiliary wheel and a transmission wheel, and is characterized in that : the operating table is arranged between the vertical plate and the vertical plate, a cross bar is arranged between the vertical plate and the vertical plate, the top plate is arranged on the vertical plate, and the cylinder one is arranged on the top plate , the adjustment plate is connected to the piston rod, the auxiliary wheel is arranged on the fixed block through the connecting shaft, and the two ends of the transmission wheel are arranged between the fixed plate and the fixed plate through the connecting rod. In the present invention, the fixing block provided with the flanging wheel and the auxiliary wheel is arranged on the pushing block through the mounting plate, and the pushing block is arranged on the piston rod 2 of the cylinder 2, so that the pushing block can move back and forth on the cross bar, driving and fixing The hemming wheel and the auxiliary wheel on the block and the fixed block move back and forth to hem the edge of the plate-shaped workpiece, which improves the work efficiency of the hemming of the plate-shaped workpiece.