I have been studying cosmic rays, relativistic charged particles originating outside of the solar system. Instead of measuring cosmic rays directly, I use X-rays and gamma-rays and "observe" cosmic rays at the accelerators (such as black-holes) or in the interstellar space, in order to understand where they are produced and how they propagate through the interstellar space. For this purpose, I have been using Japanese X-ray satellite "Suzaku" and other X-ray satellite data, and all-sky gamma-ray data of international gamma-ray satellite "Fermi". I also aim to measure polarization of X-rays and gamma-rays from black-hole binaries and pulsars in order to obtain information on the structure of accretion disk and magnatic field which is difficult (or impossible) to obtain from the imaging. For this purpose I participated in the international baloon mission "PoGO+", and participate in the X-ray polarimetry mission "IXPE".