By using particle accelerators, the field of elementary particles and nuclear physics aims to probe into the properties of elementary particles and nuclei that constitute the materials and to clarify their structure and the origin of elements and fundamental forces at work in the universe. Achievements in this field include the discovery of element 113 (Nihonium) and the awarding of the Nobel prize by Dr. Kobayashi and Dr. Masukawa. Recently, an international joint experiment was commenced using the Super-KEKB accelerator / Belle II detector, a major upgrade of KEKB, which contributed to the awarding of the Nobel prize. MEXT promotes pursuing the fundamental laws of nature and developing cutting-edge particle accelerators.