This study is focused to make investigation of the frequency of foul plays which occurs in the process of each playing time. For this purpose 4 high school games which are about same level at the 64th National Athletic Meets and 2 college games of the last day of the College Rugby football League in 1983 were singled out as subjects. The results of the study are summarized as follows: 1. The highest frequency of the scrums in each playing time occurs between 0 and 5 minutes in the first half both in the high school games and in the college games. 2. The highest frequency of line-outs in each playing time occurs between 25 and 30 minutes in the first half in the high school games and it occurs between 10 and 15 minutes in the latter half in the college games. 3. The highest frequency drop-outs in each playing time occurs between 25 and 30 minutes in the first half and latter half in the high school games and it occurs between 10 and 15 minutes in the first half and between 5 and 10 minutes in the latter half in the college games. 4. The highest frequency of penalty-kicks in each playing time occurs between 25 and 30 minutes in the first half in the high school games and it occurs between 30 and 35 minutes in the first and latter half in the college games.