On investigating the questionnaire-type diaguosis of personaiity, we find a methodological problem. It is that responses to the test items of the questionnaire-type instrument are not mutually independent, but a correlative reflection, as a whole, of the subjects' inner state. For the function of the each item to subjects Is determmed by the subjects' inner state, it does not always agree with the test-nlaker's expectations If this is proved by the further investigation, this methodology df diagnosis of personality will lead to a serious problem. In this paper, we dealt with one of the most standardized questlonnaires YATABE-GUrLFORD PERSONALITY INVENTORY, all the items of 12 scales of which the inventory is made were correlated with each other item.