A stepped substrate coating composition for forming a coating film having planarity on a substrate, including: a main agent and a solvent, the main agent containing a compound (A), a compound (B), or a mixture thereof, the compound (A) having a partial structure Formula (A-1) or (A-2):




and the compound (B) having at least one partial structure selected from Formulae (B-1)-(B-5), or having a partial structure including a combination of a partial structure of Formula (B-6) and a partial structure of Formula (B-7) or (B-8):





where the composition is cured by photoirradiation or by heating at 30° C.-300° C.; and the amount of the main agent in the solid content of the composition is 95%-100% by mass.