Multi-function writing instrument comprising a leadholder system

The invention relates to a multi-function writing instrument (10) comprising a body (12) extending in an axial direction (A) and a radial direction (R), and having at least two writing elements arranged inside the body (12), each writing element comprising a writing head and a button (28), at least one button (28) extending in the radial direction (R) through a window (26) and allowing the writing element to be moved between a retracted position in which the writing head is retracted into the body (12) and a writing position in which the writing head projects from the body (12), and one of the writing elements being a leadholder system comprising a leadholder mechanism and a lead container, the button (28) of the leadholder system comprising a lead-insertion channel extending in the axial direction (A).