We developed crystallization method of a protein molecule by laser irradiation, and call this process Laser Irradiated GrowtH Technique (LIGHT) . Effective crystallization was confirmed by applying a femtosecond laser. The crystallization period was shortened by LIGHT. Protein crystals were also obtained by LIGHT from normally uncrystallized conditions. These results indicate that laser irradiation generates crystal nuclei; protein crystals can then be grown from the nuclei that act as seeds in a supersaturated solution. We should optimize the laserirradiated condition to control the number of crystals and to obtain high-quality crystals because protein crystallization depends on the conditions.