Elementary science textbooks are the major instructional materials which contain sceientific objectives to be acquired by students. The purpose of this study is to analyze the development system, to evaluate the inquiry activity in current elementary science testbooks, and to make suggestions for the improvement of them. The questionnaires were administered to 116 subjects that participated in development of the 5th elementary science textbooks, and 86 of the subjects responded. Based on the data gathered and analyzed in this study, the major findings are as follows. First, regarding the analysis and evaluation of elementary science textbooks. 1. The instructional objectives in elementary science textbooks are analyzed. The proportions of comprehension objectives is 38%, scientific inquiry process objectives 21%, experimental skills objectives 7%, scientific attitudes and interests objectives 4%. 2. The science concepts in elementary science textbooks of the 3rd grade required the preconcrete operational level(82%) and of the 6rd grade required the postconcrete operational level (73%) by J. Piaget 3. The inquiry activities in elementary science textbooks are emphasizing gathering and organizing results and evaluation, and hypothesizing and designing an experiment Inquiry index of the elementary science textbooks is 76. This is significantly higher than 35${sim}$50 of America and U.K.. 4. The number of questions per class hour is mostly three, and most of them require the students to explain phenomena in nature or in experiment Second, regarding the development system of elementary science textbooks. 1. The budget for and the period of the development of elementary science textbook should be expanded. 2. For the improvement of elementary science textbooks, more abundant resources and time should be used for the basic study and the field trial of textbooks. 3. The elementary science textbook must include the affective objectives as well as the scientific knowledges and scientific inquiry skills. 4. It is not desirable to assign equal number of pages to the content of physics, chemistry, biology, and earth science. 5. Closer cooperation system is needed among the ministry of education, development research center and the field trial schools.