Composite of steel and resin and method for manufacturing same

A composite of steel and resin, comprising:

• an aluminum-plated steel sheet with a surface configuration in which three-dimensional protrusions having a minor diameter of at least 0.3 μm and a major diameter of at least 3 μm are scattered over a plane part so that, as to surface roughness profile, mean length of profile element RSm is in a range of 20 to 50 nm and maximum height of roughness profile Rz is in a range of 1 to 8 μm 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, and in which the surface of the three-dimensional protrusions is mainly a ceramic containing silicon and the plain part is mainly a ceramic containing aluminum, the surface configuration of the aluminum-plated steel sheet being obtained by subjecting the aluminum-plated steel sheet to a specific chemical reaction treatment;
• and
• a molded article of resin composition with main component of a hard, crystalline thermoplastic resin joined with the aluminum-plated steel sheet through injection molding in which molten resin is injected into the metallic mold, where the aluminum-plated steel sheet have been inserted, and molten resin penetrates into the fine recesses and is solidified.