In the composite, an aluminum-plated steel sheet and a resin are securely and integrally joined together. Through chemical etching, the aluminum-plated steel sheet is caused to have a surface configuration, in which three-dimensional protrusions having shapes with a minor diameter of at least 0.3 μm and a major diameter of at least 3 μm are scattered over a plain part and a portion covered with shallow fine recesses with a diameter of 20 to 50 nm in a state of being distributed adjacent to each other on the plain part accounts for 30 to 50% of the surface area of the plain part. The surface of the three-dimensional protrusions is mainly ceramic containing silicon and the plain part is mainly ceramic containing aluminum. The resin is joined through injection molding with the aluminum-plated steel sheet having been inserted into a metallic mold.