To strengthen the fixation of a clip to a writing utensil even when the clip has almost no section which carries out elastic deformation.

In a clip 9 where a normal to the sheet thickness surface which appears in the front side of a base 9a of the clip 9 and a normal to the sheet thickness surface which appears in both ends of cross-sectional circular arc of the clip 9 each intersects perpendicularly to the axis of rotation at the time of when turning force is added to the clip, a locking hole 9a2 is formed in the side face of the base 9a, and a locking projection 8d which engages to the locking hole 9a2 is formed on the writing utensil 1. The locking projection 8d (and the locking hole 9a2) presents a quadrilateral shape, and preferably is formed in right angle trapezoidal shape.