Abstract: A writing instrument (1) having a writing instrument housing (3), with a writing nib (8) protruding beyond one end of said writing instrument housing, wherein the writing instrument (1) has a machine-readable data memory. The invention provides a functional element (5) at that end of the writing instrument housing (3) which is remote from the writing nib (8) and attaching at least one subregion of the functional element (5) to the writing instrument (1) in a detachable manner, and allowing the functional element (5) or its detachably attached subregion to contain the machine-readable data memory.