My research is an observational study of star-forming galaxies and supermassive black holes that power active galactic nuclei (AGN), mainly at X-ray wavelengths as well as at other wavelengths in cosmic survey projects. The X-ray study is aimed to understand the physics in high-energy phenomena observed in galaxies undergoing intense star formation and the vicinity of central black holes in AGN. The multi-wavelength survey projects aim at understanding the formation and evolution of supermassive black holes. Presently, I am an active member of the multiwavelength projects of GOALS (Great Observatories All-sky LIRGs Survey) for local luminous infrared galaxies, SHELLQs (Subaru High-z Exploration for Low-Luminosity Quasars) for the most distant quasars, and eROSITA-Subaru/HSC collaborations for new X-ray selected AGN.