This study was designed as a longitudinal survey of life stressors and subjective fatigue symptoms in students before and after examinations and examined the correlation between the stressors and fatigue symptoms while taking any causal relationships into consideration. Three hundred and eighty-four students of both sexes ranging in age from 15 to 18 years were selected as subjects by capable extraction. The subjective symptoms of fatigue scale for youth (SFS-Y) was used to evaluate the severity of subjective fatigue symptoms. To evaluate stressors in daily life, the ADES-20 (Adolescent Daily Events Scale-20) was used. Subjective fatigue symptoms and stressor values obtained before and after an examination were compared using a paired Student's t-test. We tested the moderating effect of subjective fatigue symptoms and stressors by a multiple-indicator model in structural equation modeling, and analyzed its causal structure. Three subjective fatigue symptoms decreased in severity after the examination: "difficulty in concentrating on thinking", "weariness", and "reduced vitality". In contrast the "feeling of physical disorder", increased in severity afterwards. It was confirmed that achievement examinations were stress events which influenced subjective fatigue symptoms. It was also confirmed that life stressors changed after the examination, and that these modified the environment rather than personal cognitive appraisal. With regard to the causal relationship between life stressors and subjective fatigue symptoms before and after the examination, subjective fatigue symptoms before the examination most profoundly influenced those after it. The subjective fatigue symptoms caused by unusual life stressors before the examination probably persisted and influenced the subjective fatigue symptoms after the examination.