We discuss physics opportunities at SPring-8 using GeV-photons and MeV-photons obtained by Compton backscattering of laser photons from 8 GeV electrons. We show a principle of Compton backscattering and an overview of applying a high energy photon beam for physics experiments. A new facility at SPring-8 is under construction, aiming at physics experiments using a polarized photon beam in the energy range of 1.5~3.5 GeV. The main subject is to study sub-nucleonic degree of freedom through the measurements of various produced mesons. In addition, we present a possibility of nuclear resonance fluorescence (NRF) experiments with high intensity polarized photons at several MeV energies with an intensity of 10⁸~10⁹ per second.

PACS numbers: 13.60.Fz, 25.20.--x, 25.70.Ef