To make a double-layered coating film have good stain resistance without the necessity of car washing by using a base coating containing a polymer in which a silicate compound expressed by a specified formula is grafted onto a hydroxyl group-containing acrylic resin or a polyester resin and a melamine curing agent as resin components.

The base coating contains a polymer in which a silicate compound is grafted onto a hydroxyl group-containing acrylic resin or a polyester resin and a melamine curing agent resin components. The silicate compound is expressed by formula I, wherein m is an integer of 1-50; R1 is an organic group of 1-20C. An alcohol-modified silicate compound contained in a top coating clear coating is expressed by formula II, wherein n is an integer of 1-50; a part of R2 is a 2-20C alkyl and/or a 7-70C aralkyl, and the residual R2 is methyl.