Writing instrument with spare key.

摘要

A writing instrument such as a ball-point pen (1) has a barrell (4), a rotatable tube (5) coupled therewith, and a cap (2) detachably mounted on the rotatable tube. A spare key (8) has an end pivotally connected to the rotatable tube. The spare key is fully accommodated in the cap when the cap is mounted on the rotatable tube.