Saliva sampling has some advantages that it is non-invasive, making multiple sampling easy and stress free. The purpose of this study is to evaluate the usefulness of salivary alpha (α) -amylase (sAA) as psychosomatic stress indexes in junior high school students. Seventy healthy (not non-attendance at school) subjects in first-year junior high school students were enrolled (12-13 yr). The sAA in the morning, daytime and early-evening were analyzed for 3 days. General Health Questionnaire (GHQ) -28 and State-Trait Anxiety Inventory (STAI) were conducted as mental health indexes, the all subjects divided two groups; high and low. High stress groups either GHQ-28 (social dysfunction) or STAI (state anxiety) showed significantly high sAA compared with those of low stress groups. The multiple regression analysis using sAA as dependent variable had applied between sAA and both mental health indexes. Although, there was no significance in low stress groups, a causal relationship was found in high stress groups. These results suggested that sAA is useful index for screening of healthy human not having especially psychosomatic stress but havingthe risk before being bad mental conditions such as a state of depression. The sAA might be a useful screening method for preventing to be a non-attendance at school.