The present paper introduces a new fine probe for electric cautery (1.65 mm in diameter, 22 cm long) that can be connected to a conventional cylindrical hand-controlled cautery holder, which is monopolar and widely used in general surgery. When cautery was required, a 14-gauge intravenous catheter was inserted at an appropriate site under the guidance of a videoscope. After removing the steel inner needle, the extra tube was used as the fine surgical port for the cautery probe. The position of insertion could be altered according to the operating field. Cautery was performed by conventional methods. There was no bleeding or air leakage at the site of puncture during or after surgery. The puncture wound was closed without any sutures. Based on these results, the new fine probe for cautery can reduce the number of surgical ports required for instruments during video-assisted surgery, thus improving the ease and safety of endoscopic surgery.