US Patent 7854559 Pen with double pen barrel

A pen with double pen barrels is revealed. The pen with double pen barrels includes two pen barrels connected in parallel, a pen refill in each pen barrel, and a driving member disposed between the two pen barrels. When one of the pen barrels is pressed and moved downward, a pen refill extends out of a front end of the pen barrel, located to be in writing state. Then by releasing a stopper of the pen barrel, the pen barrel moves upward and the pen refill retracts to be in storage state. Thus the pen barrel and the pen refill extends and contracts synchronously. Moreover, interests in use of the pen are increased.