This study was performed to define the effects of Far Infrared Ray Radiation Fabrics as summer garments during outdoor work by human trial. One healthy male subject was volunteered for this study. Experimental garments consisted of three kinds of trousers (Cotton, Cotton/linen blended, Far Infrared Ray Radiation Fabric/wool blended) and basic garments (panty, socks, shirts, and dress shirts). The measurements were rectal temp., skin temp., microclimate inside clothing, heart rate, subjective sensation etc. The results were as follows : 1. Rectal temperature showed the lowest in Far Infrared Ray Radiation Fabrics among 3 garments. 2. Skin temperature (forehead, chest abdomen temp.) and mean skin temperature were lower in Far Infrared Ray Radiation Fabrics than in others, especially during early stage of work. 3. Heart rate showed lower value in Far Infrared Ray Radiation Fabrics than in others but there was no significance among the garments. 4. Humidity inside clothing and total weight loss showed the highest value in Far Infrared Ray Radiation Fabrics.