2-inch size Ce:GAGG single crystals with various ratio of Ga to Al (Ga/Al) were grown by the Cz method and the concentration of the grown crystals was measured by using EPMA. Scintillation properties such as light output, decay time and time resolution were evaluated and the dependence on the Ga/Al was characterized. As a result, the light output was reduced by increasing of the Ga/Al. On the other hand, the timing properties became worse by decreasing of the Ga/Al.