Background: In laparoscopic surgery, fogging of the lens tip instantly degrades the quality of image and interrupts the flow of surgical maneuvers. External warming devices prevent fogging for a certain length of time, but use of them is troublesome at best. These problems prompted us to develop a fogless mechanism built into the scope so that the fogless image would be continuous and trouble-free. We then conducted several experiments that demonstrate the precise effect it has on the lens tip. Methods: The infrared radiation pyrometer was used to compare the temperature distribution as well as the temperature change against time of each lens tip of the fogless and ordinary laparoscopes. Results: The temperature of the lens tip of the ordinary scope did not change, but that of the fogless scope rose to 41°C in 184–208 s. Conclusions: The fogless mechanism effectively warms the lens tip to a safe temperature that prevents fogging in the intraabdominal environment.