In this paper, in order to clear the thermal comfort zone in wearing suits, the evaluation experiment was conducted under moderately hot conditions in the steady temperature and humidity room, assumed office in summer. As a result, it was shown that there was not the gender difference of mean total heat flux, but there was the gender difference of mean sensible heat flux and mean latent heat flux. There was the gender difference of thermal comfort vote when the value of MST was 34.1°C - 35.6 °C. And it was shown that natural TSV is represented in SET* of 28.4°C in female subjects. This value was higher than the conventional value. It was clear that there was the gender difference of acceptable rate of thermal environment.