Studies on generation and application of accelerator based photon beams whose wavelength from MIR to THz has been conducted in Kyoto University. MIR-FEL facility, KU-FEL, consisted of a 40 MeV electron linac as an FEL deriver and 1.6 m undulator generates 12-14 μm photon beams with peak power of 2 MW. The material analysis laboratory has been constructed for MIR-FEL users especially for developments of energy material. Design study of a table-top THz FEL amplifier has been performed to extend the available wavelength region. © 2011 IEEE.