An experimental education was carried out to examine the following hypotheses. 1) The acquisition of conservation of length, weight and liquid measure can be facilitated by an instructional procedure consisting of verbal explanation combined with manipulating concrete materials. 2) Ss, who acquire consevation of one of these physical attributes by training, have a tendency to generalize this principle to the two other attributes. 3) Ss who comprehend conservation of an attribute also grasp its transitivity simultaneously. Ss were 40 4-to-6-year-old children, who at the pre-training test had shown neither the symptom of conservation nor that of transitivity as to any of these 3 attributes. They were divided into 4 homogeneous groups with a C. A., of 5: 5 as a mean. Three groups were served as an experimental Ss (Exp. Gr.) Gr. 1 was trained as to length, Gr. 2 weight, and Gr. 3 liquid measure, respectively. The remaining one was a control group (Con. Gr.). Each child in each Exp, Gr. received two sessions of 10-15 min. individual tranining in two consecutive days. In these sessions the E. explained conservation based on various grounds, e. i., i) identity or the material without addition or subtraction, i i) empirical reversibility of any transformation, i i i) compensability of loss in one dimension by gain in another. Post-training test was administered to these Ss 3 weeks later. The results were as follows 1) Hypothesis 1 was veriffied. Ss who were diagnosed as conservers at the post-training test were 9 in Gr. 1, 9 in in Gr. 2, and 8 in Gr. 3 in number. On the contrary, none of the Con. Gr. Ss answered all of conservation items. of any one attribute correctly. 2) Hypothesis 2 was supported. Scores of Exp. Gr. Ss as to two attributes without training increased significantly, while those of Con. Gr. Ss showed no marked improvement. 3) Hypotheses 3 also seemed tenable, because in the Exp. Grs. the number of correct responses on transitivity tasks increased significantly.