To improve water repellency, water resistance, soil resistance, etc., of a molded article by blending an unsaturated polyester resin, vinyl ester resin and the like with a specified amount of a ladder type silicone containing an acrylic group or a vinyl group.

This resin composition is obtained by blending (A) 70-99wt.% of a resin chosen from an unsaturated polyester resin (e.g. polyethylene terephalate), vinyl ester resin (e.g. polyester acrylate) or diallylpthalate resin with (B) 30-1wt.% of a ladder type silicone having (meth)acrylic group or vinyl group. The component B, for example, can be manufactured by making a silicone compound such as methyltrimethoxysilane, acryloxypropyltrimethoxysilane subjected to dealcoholating condensation. Thus, the water repellency of the molded articles can be improved without deteriorating the moldability of the resin and the physical properties of the cured article and the resin composition obtained is suitable for a building material, an automotive part material, etc.