A composition for forming a resist underlayer film has excellent storage stability at normal temperature. A composition for forming a resist underlayer film for lithography including a nitrogen-containing compound having 2 to 6 substituents of the following Formula (1) which bond to nitrogen atoms in one molecule, a polymer, a compound that promotes a crosslinking reaction, and an organic solvent. The nitrogen-containing compound having 2 to 6 substituents of Formula (1) in one molecule is for example a glycoluril derivative of the following Formula (1A). In the formula, each R1 is a methyl group or an ethyl group, and R2 and R3 are independently a hydrogen atom, a C1-4 alkyl group, or phenyl group.