The utility model discloses a grease feeding device for a grease gun and belongs to the field of machinery. The grease feeding device comprises a cylinder, a piston, a connecting rod, a handle, a rotating plate, a stroke plate, a rotating shaft fixing seat and a grease outlet pipe, wherein one end of the grease outlet pipe is communicated with a cavity of the cylinder through the lower end of the outer side of the cylinder, the rotating shaft fixing seat is fixedly connected with the upper end of the outer side of the cylinder, one end of the stroke plate is movably connected with the upper end of the rotating shaft fixing seat, one end of the handle is movably connected with the stroke plate, the portion, with the preset distance to one end of the handle, on the handle is fixedly connected with the upper end of the rotating plate, the preset distance is smaller than a half of the length of the handle and larger than a half of the width of the cylinder, the width direction of the cylinder and the length direction of the handle are on the same plane, the piston is in a ring shape, the piston is arranged in the cavity of the cylinder, the piston is in sleeve connection to the outer side of the lower end of the connecting rod, the connecting rod is in a cylindrical shape, and the upper end of the connecting rod is movably connected with the rotating plate. The grease feeding device solves the problem of being poor in grease feeding effect for the grease gun, improves the grease feeding effect for the grease gun and is applied to feeding grease for the grease gun.