An electrosurgical apparatus comprises: a main body formed with a suction passage therein； an extension member including a length adjusting tube coupled to a side of the main body and formed therein with an induction passage communicating with the suction passage, and a sliding part configured to slide while being guided by the length adjusting tube； and a blade configured such that a first end thereof protrudes outside through the sliding part, and a second end thereof extends to be electrically connected to the main body and receives high frequencies from the main body, wherein an entire length of the extension member is adjusted according to a position of the sliding part sliding along the length adjusting tube.
