Some 800 pupils in public schools from the second to the nineth grade were examined in their Like-Dislike attitudes toward their classmates by means of a sociometric test, and then in their evaluation of personality by means of a guess-who-test composed of 22 items. Both tests were twice administered with an interval of a week. The results obtained are as follows : 1) Thers are remarkable tendencies among the pupils to evaluate positively in the guess-who-test those toward whom they express their positive attitudes in the sociometric test (p→p), and to evaluate negatively those toward whom they have negative attitudes (n→p). There is, however, hardly any tendency to evalnate negatively those toward whom they reveal positive attitudes (p→n), or to evaluate positively those toward whom they express negative attitudes (n→p). The former is considered as a balanced situation, whereas the latter as an unbalanced situation. So it may be said that a balanced situation tends to be searched for and that an unbalanced situation to be avoided. This agrees very well with Heider's theory. 2) Although the combination, p→p, is more frequently found than the combination n→n, the difference of frequency between the combinations, p→n and n→p, is insignificant. This means that our results support partly Jordan's hypothesis as to the pleasantness-unpleasantness factor in selection. 3) It may be said from the above findings that the friendship relations have considerable influence upon the mutual evaluation of personality. This influence is most conspicuous at the grades from fourth to sixth, and it tends to diminish from the seventh grade on. 4) The influence is greater on the evaluation of "social items" than "individual items."