To obtain the subject composition containing a water insoluble powder, capable of cleaning the surface of a plastic material with suppressing a scratch formation at the surface of a soft material such as a plastic while maintaining an abrasive cleaning power to an adhered stain on the surface of the above material.

This detergent composition for the surface of a plastic material contains 2-10wt.% nonionic surfactant and 40-60wt.% water insoluble powder having 2-7 Moh's hardness. In this case, the nonionic surfactant is one or more kinds of surfactants selected from a fatty acid alkanolamide or an alcohol ethoxylate having a 6-12C alkyl group, and contains the water insoluble power having ≤10μm mean particle diameter and containing ≥50% power having <10μm particle diameter as a particle size distribution thereof.