Retractable writing instrument

A retractable writing instrument, comprising a pen point, a clip, and a barrel, the pen point being configured to be in a state of projecting from the barrel or a state of being retracted into the barrel by sliding the clip in a longitudinal direction of the barrel, wherein

• the clip includes a clip body, a holding portion, and a clip base,
• the clip body includes one upper wall extending in the longitudinal direction of the barrel and a pair of side walls formed at least on a front side of the upper wall, projecting from both side portions of the upper wall in a direction of a surface of the barrel, and having inner surfaces facing each other,
• the holding portion is provided on a back side of the clip body and between the pair of side walls, has a shape capable of producing an elastic force by deformation, and projects more in the direction of the surface of the barrel than the pair of side walls,
• the surface of the barrel includes a guide groove extending in the longitudinal direction of the barrel and provided with a pair of side surfaces to restrict lateral movement of the holding portion,
• the clip base is connected to a rear side of the clip body and supports the clip body at a height not to cause the pair of side walls to contact the surface of the barrel,
• the upper wall of the clip body has a shape with an increasing width from the front side to a rear side,
• the pair of side walls of the clip body are formed from a front end to a rear end of the upper wall,
• on a rear side of the pair of side walls, a pair of engagement portions are formed projecting inside the clip body,
• at a front end of the pair of engagement portions, a pair of stopper walls are formed projecting toward a back surface of the upper wall, and
• the pair of engagement portions engage with both sides of the clip base and the pair of stopper walls abut on a front surface of the clip base.