The present study was aimed to survey the relation between habitual exercise and the quality of nocturnal sleep. Questionnaires on exercise behavior and sleep were given to 452 male and female university students. The questionnaires included such questions as; on their habitual exercise, the kind of exercise, duration and frequency of doing the exercise, the period of continuation, rating of perceived exertion (RPE) and subjective feeling of their exercise load for health (heavy, suitable, light) . TMIN Life Habits Inventory were conducted to ascertain the quality of sleep. The results of all the students showed that they were more likely to experience insufficient asleep period (64.6%), were not refreshed in the morning (40.0%), found unbearable daytime napping (38.5%) . The student group with habitual exercise (n=237) showed significant “more easily fall asleep” (p<0.05) and “more insufficient asleep period” (p<0.05) tendencies than the group without habitual exercise. Further, three groups divided by their subjective feeling toward their exercise load showed some significantly different quality of sleep. The students who felt that their habitual exercise was “suitable” or “light” showed better sleep, with reference to frequency of mid-sleep awakening and deepness of sleep, as compared with students who felt that their exercise was “heavy” (p<0.05) . These results indicate that suitable or light habitual exercise might facilitate better quality of sleep, while heavy exercise which strongly activate the sympathetic nervous system, pose a risk to disrupt sleep.