The physiological and psychological effects of air temperature and humidity on the human body during physical exercise in the summer were investigated. The experiments were carried out in a climate chamber at Nara Women's University at three different air temperatures (30℃, 32.5℃ and 35℃)and at four different relative humidities (30 %, 50 %, 70 %, and 90 %). The mean radiant temperature was equal to the ambient temperature and the air velocity was less than 0.2 m/s. The subjects were four young healthy women and they wore bra and panty (about 0.03 clo). The exercise intensities were 25 W and 50 W. After the subjects staved in the chamber for more than 30 minutes, they pedaled bicycle ergometer at the rate of 50 rpm for 30 minutes. The physiological responses of the human body (skin temperatures, rectal temperature, heart rate, metabolic rate, body weight) were measured. Mean skin temperature was calculated from the weighted mean formula by Hardy and DuBois. Skin wettedness was calculated from body weight loss, mean skin temperature and metabolic rate. The psychological responses (thermal sensation vote, comfort vote, evaluation of environment and so on) were asked. The results were as follows: (1) The higher the air temperature and the relative humidity are, the higher the mean skin temperature is. The stronger the exercise intensity becomes when the relative humidity is above 70 %, the higher the mean skin temperature is. In view of the relation between the mean skin temperature and the comfort vote, the higher the mean skin temperatures are, the more uncomfortable side votes increase. As the mean skin temperatures are above 34.5℃ at rest and above 33.5℃ at 50 W, the uncomfortable side votes increase. (2) The higher the air temperature and the relative humidity are, the heart rate increase. When the exercise intensity is strong, the effects of the air temperature and the relative humidity on the heart rate are observed. When the heart rate is more than 130 beats/minute, the uncomfortable side votes increase. (3) The higher the air temperature and the relative humidity are, the higher the skin wettedness is. When the exercise intensity is strong, the effects of the combination of the higher the air temperature and the higher the relative humidity on the skin wettedness are seen. The uncomfortable side votes can be observed when the skin wettedness is above 0.2 at rest and above 0.4 during exercise at 50 W. The ineffective sweat rate increases when the skin wettedness is above 0.4. (4) The contour lines of the mean skin temperature, skin wettedness, and comfort vote, are shown on psychrometric charts. In the light of them, the thermal uncomfortable zones of rest and exercise can be comprehensively examined. (Fig.18) (5) The thermal uncomfortable zone is at the lower end of the Discomfort Index and the WBGT Index and estimates the effects of humidity less than them. Whereas the thermal uncomfortable zone is at the higher end of the comfort lines set by Nevins et al., Rohles et al., Fanger and SET*, and shows the effects of humidity more than their comfort lines.