In aerospace and automotive fields, research and development of structure using CFRP which has high strength and lightweight are promoted. Recently, thin-ply materials (less than 0.1 mm in thickness) which have an extremely low aerial fiber weight produced by using a fiber tow spreading technology (ITCF Method) have attracted a significant attention. There are lots of studies indicating that various mechanical properties of CFRP laminates are improved by use of thin-ply materials.