A novel production method enables selective production of an isocyanuric acid N-substituted product of interest in one pot, requiring neither multiple steps nor cumbersome treatment, the method producing an N-(hydrocarbon)isocyanuric acid which includes a step N for reacting, in a solvent, a dihalogenated isocyanuric acid derivative with at least one hydrocarbonization agent selected from the group consisting of a halogenated hydrocarbon compound, a pseudo-halogenated hydrocarbon compound, and a dialkyl sulfate compound.