A multi-refill writing instrument includes a barrel, writing bodies accommodated in the barrel so as to be movable back and forth, elastic bodies urging the writing bodes backward, operating bodies connected to rear ends of the corresponding writing bodies and window holes formed in a side wall of the barrel so as to extend in the axial direction. The operating bodies protrude from the barrel to an outside through the window holes in the radial direction, one of the operating bodies slides forward along the window hole so that a nib of the writing body connected to the one operating body protrudes from the barrel through a front hole, and a nib of another writing body in a protruding state is retracted into the barrel, and the writing bodies and the operating bodes are pulled out from the barrel and inserted into the barrel.