In order to obtain the basic data for the relationship between factors related to sports and bone density of high school girls, bone densities of a heel were measured, and physical characteristics and living backgrounds on exercises were surveyed. The subjects were one-hundred and forty two girls (15-18 years, mean±SD=16.5±0.84 years) of a high school in Nagano prefecture, accepted our visiting bone health check. Bone density was measured by ultrasound bone-densitometer ‘Achilles’ (Lunar) . As for the data, we obtained the stiffness index (Stiffness) with a self-registered questionnaire for the items of physical and exercise factors for the girls in puberty. High school girls who belong to a sport club have significantly higher bone density than other girls. In detail, those who do the sports which consist of mainly running or jumpping, have significantly higher bone density than others who do no sports. There also were significants on the kinds of sports, on the frequency of sports and on the duration of sports. Moreover, those who had the regular sports history have higher bone density than those who had no regular sports history, and the mean Stiffness of the group that care to do physical exercises daily was higher than those who do not care to do exercises. These results suggest that there are many kinds of factors related to sports which favourably contribute to obtain sufficient bone mass of high school girls who are in a developmental stage.