A step substrate coating composition for efficiently forming a coating that is capable of filling and flattening a pattern. A step substrate coating composition comprising a compound (A) of a main agent, a crosslinking agent, and a solvent, the compound (A) including a partial structure expressed by formula (A-1) (where the broken line represents bonding with an aromatic ring, the aromatic ring forming a polymer skeleton or a monomer, and n represents an integer of 1-4).