The purpose of this study was to make clear the relationship between body temperature and lifestyle in elementary school children. The subjects were comprised of 79 boys and 102 girls in children from third to fifth grader. The investigation was carried out by the measurement of body temperature and questionnaire of lifestyle from November to December 2008 and the same period 2009. The body temperature was measured in an axilla for 10 minutes. The questionnaire was composed the sleep onset time, the getting up time, the TV hour, the game hour, the internet/mobile telephone hour, the exercise hour, the learning hour, the evacuation situation and the breakfast intake situation. The main findings were as follows : 1) The issue of low body temperature tendency worried about since 1980s was not still solved. However, about 20% of all measured values was more than 37.0°C. 2) The group of low body temperature which was less than 36.0°C at the time of getting up showed a low temperature level through day. 3) The group of high body temperature which was more than 37.0°C at the time of getting up showed a flat temperature change through day. 4) The relationship between temperature and lifestyle in girls was not clarified. On the other hand, it was shown that the internet/mobile telephone hour was long, the sleep onset time was late and the sleep hour was short in low body temperature group of boys.
