PROBLEM TO BE SOLVED: To solve the problem that a cam or a locking part is destructed if a rotary operation force of a necessary degree or more is applied by mistake at the time of taking in and out operation of a writing body unit and there might bring about trouble in the taking in and out operation of a writing body unit and, in a rotary let-out type composite writing utensil having no locking part, a threading means is hard to use in the joining of relatively rotating front and rear barrel parts and the selected writing body unit cannot be recognized. SOLUTION: In the rotary let-out type composite writing utensil wherein a plurality of the writing body units are arranged in a barrel 2 and taken in and out by the rotation of a cam 6, locking steps are provided at the barrel, and locking parts locked with the locking step parts are provided at a rotary member attached to the barrel, and the locking step parts are formed so as to be able to elastically deform at least one of the locking parts. COPYRIGHT: (C)2003,JPO