Disclosed is a transparent composite material which has a small linear expansion coefficient and has excellent transparency, flexibility, and workability, and is obtained by curing a resin composition containing a synthetic smectite having a number average particle diameter of 10 to 300 nm and an aspect ratio of 10 to 300 and having been organified with a quaternary ammonium salt and/or a quaternary phosphonium salt in an amount of 10 to 55% by mass dispersed in a resin component containing an epoxy (meth)acrylate synthesized from a lactone-modified (meth)acrylate, an acid anhydride, and an epoxy resin. Further disclosed is a transparent composite sheet comprising the material.