The temperature at which the highest photosynthetic rate of grapevine varieties was obtained was at a range of 20-30℃, though the optimun temperature varied depending on the varieties. The photosynthetic rate obviously declined at lower or higher temperature than that. The evapotranspiration (ET) rates of the varieties generally increased as temperature increased, and the rate was the highest between 30-35℃. stomatal conductivity, CO_2 concentration inside cell spaces and water-use efficiency reached the maximum at 15-20℃. Thereafter, they decreased as temperature increased. The photosynthetically optimum temperature zone of the European cultivars, except for ‘Chasselas rose’ and ‘Nyunai’ which are cultivated in cool regions, was of higher one than that of the American cultivars. That might be the result of the selection conducted for the cultivars under the temperature conditions in the cultivated areas. Therefore, it is possible that the varieties having the same family relationship have different temperature requirements. On the other hand, the photosynthetically optimum temperature zone of many American cultivars was of low one. At 35℃, their photosynthetic rate was higher than that of the European cultivars except for ‘Neo Muscat’ and ‘Italia’. Therefore, the photosynthetically optimum temperature zone of the varieties that have high photosynthetic rate at high temperature was not always of high one.