[en] This paper reports on quasi-monochromatic photons of energies 1.6-8.7 MeV generated by the Compton backscattering of laser light on relativistic electrons in a storage ring TERAS installed at the Electrotechnical Laboratory. Spectra of the backscattered photons have been measured with an anti-Compton spectrometer system. The present system consists of a coaxial type pure Ge detector of 155 cm³ as a central detector and a well type NaI(Tl) scintillator of 8 in. φ x 8 in. as an outer one. With a usual anti-coincidence technique, clear photopeak spectra were obtained with the Compton suppression ration of 2-4. The maximum energy and the energy spread of photons show reasonable agreements with numerical calculations. The divergence and energy spread of the electron beam in the storage ring is estimated from the data