To provide a multi-refill writing utensil which can easily replace a frequently used refill whose ink is depleted with a new one and thus can be continuously used for a long period of time.

In the multi-refill writing utensil which houses a plurality of refills 30 urged backward by a spring member 39 in a barrel 10, then advances a slider 40 fitted to the rear end part of the refill 30 and selectively ejects a pen element 31 of one refill 30 from the tip opening 15 of the barrel 10 by engaging the slider 40 with a securing part 16 of the barrel 10, a retaining part 22 is formed in one of through holes 21, of a plug 20, for each refill 30 to be inserted through and a spare refill 50 to be incorporated into the barrel 10 is inserted through the insertion hole 21 where the retaining part 22 is formed and retained by the retaining part 22. In addition, a longitudinal rib 14 is formed at the rear end part of the barrel 10 and the tail end part of the spare refill 50 retained by the plug 20 is brought into contact with the tip edge of the longitudinal rib 14 and positioned.