A hand-operated vacuum pulling device includes a shank, over which a backward ram is slidable fit. The shank has a front end to which a suction cup is attached and a rear end to which a handgrip defining a cylinder and having a pressure relief seat is attached. The pressure relief seat forms a ram stop at a joint thereof with the shank. The handgrip has a rear end to which a ring-shaped cover assembly is attached. The piston assembly is manually operable to induce a vacuum inside the cylinder. And then, the ring-shaped cover assembly can be manually operated to pull the piston assembly backward for repeated operation of the piston assembly to thereby make a spring contained in the piston assembly stiffer and increase the suction power of the suction cup. The backward ram can be quickly moved backward to impact the ram stop for improving pulling effect.