Abstract: A writing utensil such as a fountain pen is provided with an erasing assembly having a sealing cap which closely covers the wick and is fitted onto the erasing tip in a form molding and friction holding manner; the open end of the cap is provided with an external thread, a similar external thread is formed at the erasing cartridge end of the erasing tip, the pen barrel and the end cap have corresponding internal threads and are threaded onto either the sealing cap or erasing cartridge.