Changes are expected in the future, and the future society will expect changes in education. Science curriculum needs to reflect such demands for changes in the future of education. Hence, this study explored ways to reflect the changes demanded by the future society in science education. In this study, we investigated the major issues and directions for improvements based on the findings from questionnaires given to 447 primary and secondary school science teachers as well as in-depth interviews with 12 experts. We explored the problems of the 2009 revised national science curriculum including organization of science elective courses, fusion 'science' as an elective course, intensive course-taking of science, career-focused science curriculum, variation of completion units in science elective courses, and fairness of science elective course selection in college entrance. In addition, we proposed ways to organize science curriculum around core competencies and STEAM education suggested by science teachers. According to the results, we need to add such key competencies as basic learning abilities, self-identity, and moral competencies to science curriculum in addition to existing key competencies including problem solving and communication. Regarding the fusion science, experts contended that convergence of science courses should come before that of science and other subjects, and that STEAM with science as the axis was the desired form of convergence. We also need to establish a curriculum development center that exclusively focuses on science curriculum research and development.