Pen

摘要

A pen includes a pen tube, a connection structure, a cap and an elastic unit. The pen tube includes a pen tube case and a thread portion provided at the pen tube case. The connection structure includes a main body, a corresponding thread portion and an elastic unit fastener. The corresponding thread fastener is located at the main body and is for joining with the thread portion. The elastic unit fastener is provided at the main body. The cap includes a cap case and an elastic unit corresponding fastener provided at the cap case. The two ends of the elastic unit are respectively fastened to the elastic unit fastener and the elastic unit corresponding fastener.