Provided is a triazine ring-containing hyperbranched polymer comprising the repeating unit structure represented by formula (1) and having one or more triazine ring terminals, said one or more triazine ring terminals being capped with a compound that differs from the diamine compound serving as the starting material for the polymer and has at least two active hydrogen groups. In addition to the polymer itself exhibiting high heat resistance, high transparency, a high refractive index, high light resistance, high solubility, and low volume shrinkage, it is also possible to use the polymer to provide a composition for film formation capable of yielding a thick film having high hardness. (In formula (1), R and R′ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group, and Ar represents a divalent organic group containing an aromatic ring and/or a heterocyclic ring.)