In estimating the thermal insulation effect (TIE) by an experiment of wearing clothes on human body, lack of reproducibility and each part of clothing insulation value have been pointed out. Therefore an electrically-heated manikin was used to study the effects of clothing materials and seasonal clothes on the thermal insulation value of KMFC. The manikin consisted of a black anodized copper skin formed to simulated the size and shape of a typical man (height 170 cm, body weight 60 kg). The manikin was instrumented with 17 skin thermistor in various locations on its body. We reached the conclusion below through the comparison of western style men's clothes and Korean women's folk clothes (KWFC), The TIE for KMFC is 0.63-0.84% for summer clothes and 1.28∼1.32 clo for spring and fall ones. For the total thermal resistance (1‥‥‥) when wearing KMFC, standing position has a bigger one than sitting position, and the change by each position is more than that of western style men's clothes. For the TIE of KMFC, that thermal resistance of the back part is more than that of western style men's clothes, which is a major factor causing bigger TIE. In addition, the weight per unit area of KMFC was highly positively correlated with the keeping warm.