The laser-induced crystallization method is applied to an oxyfluoride glass with the composition of 41.5SiO(2)-21.3Al(2)O(3)-4.8CaO-12.6NaF-16.4CaF(2)-2.9NiO-0.5ErF(3) (mol%), and the lines consisting of CaF2 nanocrystals (diameter: similar to 20 nm) are patterned on the glass surface. It is found from micro-photoluminescence (PL) spectra of Er3+ ions that Er3+ ions are incorporated into CaF2 nanocrystals formed by laser (continuous-wave Yb:YVO4 fiber laser with a wavelength of 1080 nm) irradiations. Two-dimensional mappings of the PL intensity for the S-4(3/2)-> I-4(15/2) transition of Er3+ ions are measured for the surface and cross section of the patterned lines. It is found that two phases giving different PL intensities are formed in the laser-irradiated region, suggesting that the center part of the laser-irradiated region consists of Er3+-doped CaF2 nanocrystals and the surrounding of the center part gives the fluoride ion rich coordination state for Er3+ ions. The formation mechanism of Er3+-doped CaF2 nanocrystals is related to the temperature distribution of the laser-irradiated region.