| 摘要 |
A writing instrument has a cam rotatably connected to a rear end of a main body so that rotation of the cam in opposite directions within a predetermined range advances and retracts a refill housed in the main body. A sealing section seals the front end of the refill when it is fully retracted in the main body. The outer configurations of the main body and the working cam have a generally regular triangle shape in cross section, and the outer configurations are coincident with each other at the position where rotation of the working cam starts and are rotationally shifted relative to one another when the working cam is rotted, whereby the rotation state of the working cam can be discerned by the coincidence or non-coincidence of the outer configuration |
