Abstract: A pen with a swinging decoration includes a decoration in a shape with two hands and two legs at a top end of a penholder of an ordinary pen. A refill is pushed against a top shaft to move upward and pressed against a swing, whereas teeth rows at two edges of the top shaft drive conjugate gears to rotate at the same time, so as to swing the two hands and two legs having gears upward and downward at the same time, upon writing with the pen.