A curable composition comprising: a siloxane oligomer (a) containing a radically polymerizable double bond obtained through hydrolysis and condensation of alkoxysilanes containing at least an alkoxysilane A of Formula and an alkoxysilane B of Formula in an amount of 100 parts by mass; inorganic fine particles (b) in an amount of 10 parts by mass to 1,000 parts by mass, wherein the inorganic fine particles (b) are elongated-shaped silica fine particles having: an average particle diameter of 1 nm to 25 nm, where the average particle diameter is determined from a specific surface area (m 2) measured by a nitrogen adsorption method (BET method) in accordance with the expression of Average particle diameter = (2720/Specific surface area), and an average length of 30 nm to 500 nm, where the average length is determined by measuring by a dynamic light scattering method (DLS method); and a polymerization initiator (c) generating a radical upon active energy ray irradiation in an amount of 0.1 parts by mass to 25 parts by mass R 1 a Si(OR 2) 4-a R 3 b Si(OR 4) 4-b where R 1 is a monovalent organic group containing a radically polymerizable double bond; R 3 is a C 1-10 alkyl group or a phenyl group, wherein the alkyl group is optionally substituted with a fluorine atom, an amino group substituted with at least a C 1-6 alkyl group, an amino group substituted with at least a phenyl group, or a ureido group; R 2 and R 4 each are independently a methyl group or an ethyl group; a is 1 or 2; and b is an integer of 0 to 2. a siloxane oligomer (a) containing a radically polymerizable double bond obtained through hydrolysis and condensation of alkoxysilanes containing at least an alkoxysilane A of Formula and an alkoxysilane B of Formula in an amount of 100 parts by mass; inorganic fine particles (b) in an amount of 10 parts by mass to 1,000 parts by mass, wherein the inorganic fine particles (b) are elongated-shaped silica fine particles having: an average particle diameter of 1 nm to 25 nm, where the average particle diameter is determined from a specific surface area (m 2) measured by a nitrogen adsorption method (BET method) in accordance with the expression of Average particle diameter = (2720/Specific surface area), and an average length of 30 nm to 500 nm, where the average length is determined by measuring by a dynamic light scattering method (DLS method); and an average particle diameter of 1 nm to 25 nm, where the average particle diameter is determined from a specific surface area (m 2) measured by a nitrogen adsorption method (BET method) in accordance with the expression of Average particle diameter = (2720/Specific surface area), and an average length of 30 nm to 500 nm, where the average length is determined by measuring by a dynamic light scattering method (DLS method); and a polymerization initiator (c) generating a radical upon active energy ray irradiation in an amount of 0.1 parts by mass to 25 parts by mass R 1 a Si(OR 2) 4-a R 3 b Si(OR 4) 4-b where R 1 is a monovalent organic group containing a radically polymerizable double bond; R 3 is a C 1-10 alkyl group or a phenyl group, wherein the alkyl group is optionally substituted with a fluorine atom, an amino group substituted with at least a C 1-6 alkyl group, an amino group substituted with at least a phenyl group, or a ureido group; R 2 and R 4 each are independently a methyl group or an ethyl group; a is 1 or 2; and b is an integer of 0 to 2. where R 1 is a monovalent organic group containing a radically polymerizable double bond; R 3 is a C 1-10 alkyl group or a phenyl group, wherein the alkyl group is optionally substituted with a fluorine atom, an amino group substituted with at least a C 1-6 alkyl group, an amino group substituted with at least a phenyl group, or a ureido group; R 2 and R 4 each are independently a methyl group or an ethyl group; a is 1 or 2; and b is an integer of 0 to 2.