A rotation structure of an electrosurgical pen includes a pen body and a cutting tip mounted to the pen body, an extendible/retractable smoke suction tube, and a rotation assembly mounted to an end of the pen body, and a conduit rotatably coupled to the rotation assembly. The pen body has an end on which a rotary joint part is formed. The rotation assembly includes inner and outer annular members that are rotatable with respect to each other. The rotation assembly is fit over and rotatably coupled to the rotary joint part. The conduit is fit over an outer circumference of the outer annular member. In a use of the electrosurgical pen, the rotation assembly allows the smoke suction tube and the conduit to rotate relative to each other so as to allow for free rotation of the electrosurgical pen to facilitate the operation of the electrosurgical pen.
