A radiation-sensitive resin composition for forming a resist film includes a polymer including a first structural unit represented by a formula (1) and a second structural unit represented by a formula (2). The first structural unit and the second structural unit are included in an identical polymer molecule or different polymer molecules. R1 represents a hydrogen atom or a methyl group. Q represents a divalent linking group having 1 to 4 carbon atoms. X represents a monovalent lactone group. A part or all of hydrogen atoms included in the monovalent lactone group represented by X are not substituted or substituted. R2 represents a hydrogen atom or a methyl group. Y represents a monovalent lactone group. A part or all of hydrogen atoms included in the monovalent lactone group represented by Y are not substituted or substituted.