In order to understand the influences of wearing clothings with different thermal insula-tions when men were exposed from $25^{circ}C$ environment to 18$^{circ}C$ environment, thermoregulatory responses were measured on 4 healthy female college students. Subjects rested wearing T-shirts, trousers, and socks called LC(total weight 541g) at 25$pm$1$^{circ}C$, 50$pm$5% R.H. and then exposed to the room conditioned in 18$pm$1$^{circ}C$, 50$pm$5$^{circ}C$ R.H. with LC as it was(LC Type) or with T-shirts, trousers, socks, training wear upper garment, the training wear lower garment called HC (total weight 1368g)(HC Type) for 120 min. The results can be summarized as follows: 1) When subjects were exposed from $25^{circ}C$ environment to 18$^{circ}C$ environment, decrease of rectal temperature was significantly smaller in LC Type than in HC Type. 2)Increase of heat production and weight loss had no significant difference between two types of clothing. 3)Internal thermal conductance was higher in HC Type and external thermal conductance was higher in LC Type. Therefore total thermal conductance was higher in LC Type than in HC Type. 4)Decrease of skin temperature was greater in LC Type than in HC Type. 5)Subjects felt colder with LC Type than with HC Type, but did not feel differently in comfort sensation between two types of clothing. It was suggested that less decrease of rectal temperature in LC type inspite of more dry heat loss from body might be ascribed to a shift of blood from the shell area to the core area originating in the vasoconstriction and the lowered internal thermal conductance. In conclu-sion, the importance of the state of internal heat distribution in the homeostasis seemed to be reaffirmed.