Small group activity in Japan was introduced from the United States as QC circle, ZD movement and the like, but it has developed into a Japanese style form contributing much to the management of enterprises. Based on human motivation theory, the principles to activate small group activity is suggested on which a new diagnosis of small group activity is proposed here It is consisted of checklist and raderchart. The factors to activate small activity effectively have been obtained in terms of multivariate analysis for data from the new diagnosis.