Crystallization process of copper phathalocyanine was studied in inert gases by sublimation. Near the sublimation source, crystalline particles of the alpha -form is grown, and they change into ribbon-like crystals as increasing the height from the sublimation source. The crystal structure of smaller ribbon-like crystals is the alpha -form, and transforms into the beta -form with increasing the height. The same structural changes were also observed by increasing the gas pressure. The structure change from the alpha- to beta -form happened at low height and low gas pressure, when the inert gas with large atomic number is used.