A photoresist composition comprising: a radiation-sensitive acid generator that is capable of generating an acid upon irradiation with a radioactive ray, an action of the acid allowing a solubility in a developer solution to be altered; first particles comprising a metal element and having a hydrodynamic radius as determined by a dynamic light scattering analysis being no greater than 20 nm; a first compound comprising an acid-labile group; and a first solvent, wherein the first particles are a complex or a hydrolytic condensation product thereof, the complex being obtained by mixing a metal-containing compound which is a first metal compound comprising a hydrolyzable group, a hydrolysis product of the first metal compound, a hydrolytic condensation product of the first metal compound, or a combination thereof, with at least one type of organic compound represented by formula (L-1): R 1 -(-X) n (L-1) wherein in the formula (L-1), R 1 represents an organic group having a valency of n; X represents -OH, -COOH, -NCO, -NHR a, -COOR A, or -CO-C(R L) 2 -COR A, R a representing a hydrogen atom or a monovalent organic group, R A representing a monovalent organic group, and R L each independently representing a hydrogen atom or a monovalent organic group; and n is an integer of 1 to 4, in a case where n is no less than 2, a plurality of Xs are identical or different, wherein the metal element is zirconium, hafnium, tantalum, tungsten, iron, zinc, tin, or bismuth, and wherein the first compound is a first polymer comprising a first structural unit comprising an acid-labile group. a radiation-sensitive acid generator that is capable of generating an acid upon irradiation with a radioactive ray, an action of the acid allowing a solubility in a developer solution to be altered; first particles comprising a metal element and having a hydrodynamic radius as determined by a dynamic light scattering analysis being no greater than 20 nm; a first compound comprising an acid-labile group; and a first solvent, wherein the first particles are a complex or a hydrolytic condensation product thereof, the complex being obtained by mixing a metal-containing compound which is a first metal compound comprising a hydrolyzable group, a hydrolysis product of the first metal compound, a hydrolytic condensation product of the first metal compound, or a combination thereof, with at least one type of organic compound represented by formula (L-1): R 1 -(-X) n (L-1) wherein in the formula (L-1), R 1 represents an organic group having a valency of n; X represents -OH, -COOH, -NCO, -NHR a, -COOR A, or -CO-C(R L) 2 -COR A, R a representing a hydrogen atom or a monovalent organic group, R A representing a monovalent organic group, and R L each independently representing a hydrogen atom or a monovalent organic group; and R a representing a hydrogen atom or a monovalent organic group, R A representing a monovalent organic group, and R L each independently representing a hydrogen atom or a monovalent organic group; and n is an integer of 1 to 4, in a case where n is no less than 2, a plurality of Xs are identical or different, wherein the metal element is zirconium, hafnium, tantalum, tungsten, iron, zinc, tin, or bismuth, and wherein the first compound is a first polymer comprising a first structural unit comprising an acid-labile group.