PURPOSE: To enable an assured operation and high sealing properties with a simple mechanism, by providing a seal cover of a seal chamber with one end rotatable, and a series of links on end of which is connected to the seal cover and the other end of which is energized rearward by a spring.

CONSTITUTION: A front barrel 1 and a rear barrel 2 are joined by screwing to form a single main body of a writing implement. A seal chamber body 7 provided in the diametral direction of the inner periphery of the front barrel is cylindrical in shape, and is provided with a cylindrical seal chamber 8 penetrating through a central part thereof. On a tip surface 11 of the seal chamber, a disk-shaped seal cover 13 is molded integrally with the seal chamber body so that it can be opened and closed, with one end thereof functioning as a hinge 12. A coil spring 18 is provided between an O-ring retainer 16, which fixes an O-ring 10 to the seal chamber body, and a spring retainer 19, and a writing element 20 filled with an ink is inserted in the main body of the writing implement. The writing element is constantly retracted toward the inside of the main body by the spring. One end of the spring energizes a link mechanism 40, 43, 46, whereas the other end is connected to the seal cover so that the seal cover seals the seal chamber under the force of the spring, thereby preventing a writing part at the point from being dried.