This report is the summary of our investigations made into the handling of curricula by each senior high school in Saitama Prefecture, beginning in 1956 and continuing for three successive years. The object of our research is to make clear the ways how these schools accepted the new curriculum revised by the Ministry of Education; together with the obstacles faced by them and the effects produced on them; and so to provide some helpful suggestions for a desirable future revision of the high school curriculum. As regards the full-time general courses of study these schools adopted all the five courses the Ministry instructed to them in the first year, but lowered the number of the courses in the second year, and cut it down even more in the third year, simplifying their contents as well. There are noticeable variations in the nature and contents of the adopted courses between mixed and unmixed schools. Difference among environning local communities are also reflected in their courses. The course system according to which each school adopted the courses of its own choice, gave rise to scholastic disparity among them. Some schools (chiefly boys' high schools) where the greater majority of students desire to go on to schools of higher grade, tend more and more to concentrate their efforts in coaching the students for the entrance of colleges and universities; while other schools (chiefly coeducational ones) are forced to manage a number of different courses, apparently hurting their educational efficiency. As regards the full-time vocational courses of study the Ministry of Education mapped out a variety of courses, which excepting that of engineering, are all hardly practicable. Though the units of each general subject were made to range from three to five, and it serves for the purpose of widening the sphere of general arts, the unfavorable result is that a heavy burden have fallen on the students. Because the whole units, including those of general and vocational subjects, have exceeded far above the regulated eighty-five units. In the part-time courses, both general and vocational, it is virtually impossible to follow the course system, owing to a great number of students with its insufficient teaching staff. The time seems to come again when the high school curriculum is in need of re-examination. High school education will not be made better merely by manipulating its curriculum, while leaving the term of its study and the number limit of its teacher as they are now. Difficulties will not be overcome unless some drastic measures are taken, with regard to the system itself and its financial conditions.