To make an inner cap slidable without complicating a structure and deteriorating assembling workability, in regard to a cap for a writing implement having the structure wherein a spring for giving springiness to a clip is provided in a cap body and which has an inner cap for ensuring airtightness.

An engaging groove 17 and an engaging protuberance 21 are formed in a suspension screw 10 fixed to a crown 8. The inner cap 22 in a bottomed shape is formed in a shape of having a head end 23 and a tip-narrowed projecting part 25 which extends axially in front of the head end 23 and has a cut groove 24 opened forward, and the inner cap 22 is fitted so that it is slidable to the head end 3 side of the cap body 2 by making an engaging projection 25 formed on the inner cap engaged with the engaging groove 17 and by making an engaging projection 28 engaged with the engaging protuberance 21. The inner cap is brought into contact with the edge of a first space 15a formed in the shape of a suspension frame 10 on the outer periphery of the protuberance 21 and made slidable longitudinally in the cap body by the inward deformation of the projecting part 25 caused by the cut groove 24.