Knock type writing tool

Abstract

A knock type writing tool is provided, in which an appropriate amount of air can be taken in depending on an amount of a thermochromic ink discharged from a pen tip, so that the thermochromic ink can be smoothly discharged from the pen tip, and in which a writing body can rotate surely in conjunction with a rotation of a rotating member. An air holeand a plurality of projection piecesare provided at a rear end portion of a writing body. A front surface of a projection and retraction rotating memberis provided with a plurality of abutment parts, on which respective rear ends of the plurality of projection piecesare to abut, and with a plurality of protrusion parts, each of which is formed between the plurality of abutment partsand protruded more forward than the plurality of abutment parts. The protrusion partsare respectively inserted in gapsbetween the projection pieces. An axial length of each projection pieceis longer than an axial length of each protrusion part, so that a portion of the gapis left more forward than a front end of each protrusion part