The clothing comfort is an important ploblem in the human helth, besides, the clothing safety is drastic requirement when outdoor sports. It is considered that the careful choice of the fiber materials of underwear is necessary for these cases.
　In this report, the wear-tests of the underwear materials were carried out in two cases. One was examined to the underpants with right leg and left leg constructed different fiber materials between both sides in the cold outdoor. The other was investigated to three kinds of undershirt under the anbient temperature of 5°C and -20°C in the climate chamber.
　From the underpants test, every materials were generally comfort. However, it was inclined to discomfort by the moisture properties of composed fiber materials under the terrible climate condition or hard outdoor exercise. Furthermore, the frost and ice were formed in the reverse side of the hydrophobic outer jacket with the moisture transport from the body in the very cold climate chamber at a temperature of -20°C.
　The results of this study suggested that it was important to study the best combination of underwear materials and layered system of clothing for keeping the safety and comfortability in the outdoor sports.

DESCENTE SPORTS SCIENCE Vol.18/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE