An invertible ink stamp comprises an ink absorber/retainer member disposed on top of the ink pad, an absorbent member disposed on the top of the ink absorber/retainer member and having capillary attraction weaker than that of the ink absorber/retainer member but sufficient to absorb excessive ink, the absorbent member having a vent in at least part of the top side or either of lateral sides for conducting to the atmospheric air, an ink tank having an ink supply tube that has its distal open end connected to the ink absorber/retainer member, and a wall member surrounding the whole circumferential surface of the ink absorber/retainer member for avoiding leakage of ink.