A radiation-sensitive composition containing a resist compound having a high sensitivity, a high resolution, a high etching resistance, and a low outgas which forms a resist pattern with good shape and a method of forming a resist pattern and novel compositions for forming a photoresist under coat film which is excellent in optical properties and etching resistance and contains substantially no sublimable substance and an under coat film formed by the composition. Radiation-sensitive composition containing a solvent and a cyclic compound having, e.g., a cyclic compound (A) having a molecular weight of 700 to 5000 which is synthesized by the condensation reaction of a compound having 2 to 59 carbon atoms and 1 to 4 formyl groups with a compound having 6 to 15 carbon atoms and 1 to 3 phenolic hydroxyl groups, and a cyclic compound for use in the radiation-sensitive composition.