A stamp comprises a stamp
assembly (1) with a
cutting tool (2) mounted inside. A tool seat (30) of the
cutting tool (2) has an inclined blade recess (3012), where a moving element (32) and a blade (31), connected together, are mounted in. An operating element (34) is mounted in the tool seat (30) and combined with a resilient unit (33), connectting to the moving element (32). When disposed at an idle or extending-out position (3022, 3023) of the tool seat (30), the operating element (34) is fixed by the resilient unit (33) while the blade (31) is fixed through the moving element (32). When forced, the operating element (34) detaches from the tool seat (30) to be moved, and the blade (31) is driven by the moving element (32) to extend out of or retreat back to the tool seat (30).