A study has been made of the luminescence during Tb-ion implantation in Al2O3 or by Ar- or He-ions bombardment to Tb-ion implanted Al2O3. The substrates used were colorless and transparent single crystal ɑ-Al2O3 with (0001) or (1102) surface orientation. Ion implantations of Tb-ions in Al2O3 were carried out at fluences of 1x1013 to 1x1017 Tb/cm2 at 100 keV at nearly room temperature. Change in color of Al2O3, substrates by Tb implantation was invisible to the naked eye. The luminescence spectra were measured by Ar (100 keV) or He (50 keV) bombardment to Tb implanted Al2O3 or during Tb implantation into Al2O3 using a spectroscopy with three optical filters and photomultiplier. The luminescence spectra during Tb implantation into AljOj have four clear peaks identified as emission due to D-F transitions of Tb3+ state. The luminescence spectra of Tb implanted A12O3 excited by He, Ar and Tb bombardment were almost the same except for the luminescence at the wavelength ranging from 300 to 450 nm, which is caused by strong emission from A12O3 itself. The peak of the luminescence appears at 550 nm, and its intensity depends on the Tb dose. The maximum intensity of luminescence during Tb implantation at room temperature is obtained as the maximum atomic ratio of implanted Tb is 2–3 atomic %.