A radiation-sensitive composition contains: a polymetalloxane including a structural unit represented by formula (1); a radiation-sensitive acid generator; and a solvent. In the following formula (1), M represents a germanium atom, a tin atom or a lead atom; Ar1 represents a substituted or unsubstituted aryl group having 6 to 20 ring atoms or a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms; R1 represents a monovalent organic group having 1 to 20 carbon atoms, a hydrogen atom, a halogen atom or a hydroxy group; and n is 2 or 3.