The purpose of this study was to clarify the trends in the variation within the day, and between days, of subjective symptoms of fatigue (SSF) in the daily life of male students. A SSF questionnaire (54 items) with guaranteed validity and reliability was administered to 104, 15-16 year-old healthy students, 3 times a day, in the morning (about 08:50), mid-day (about 12:10) and afternoon (about 16:10) for 5 days from Monday to Friday. As the main statistical analysis, two-way (day and week) ANOVA and post-hoc t tests were used. The SSF questionnaire was considered to have very high reliability because Cronbach's alpha coefficients in each survey point of time were .967-.977. SSF complaints between days were low on the whole, but complaints of drowsiness were relatively high. The trends in variation of SSF between days were greater than those within the day. The trends in variation within the day were noticeable in complaints regarding drowsiness and loss of vigor. Complaints regarding languor became high from the middle of the week to the weekend. On the other hand, SSF complaints except for languor, were high at the beginning of the week, especially on Monday and became lower after Tuesday. There is a trend in variation within the day for symptoms regarding drowsiness and loss of vigor. The trend in variation between days was confirmed for many SSFs, and was noticeable as compared to those within the day. Complaints regarding languor were high on the weekend, and SSF complaints except for languor were high at the beginning of the week, especially on Monday.