An optical element comprising: a base material having a surface; and a plurality of structures which are arranged on the surface of the base material at a fine pitch equal to or shorter than the wavelength of visible light and which each comprise a convex or concave portion, wherein an elastic modulus of a material forming the structures is 1 MPa or more and 1200 MPa or less, the surface on which the structures are formed is hydrophilic, in that a water contact angle on the surface on which the structures are formed is 30° or less, and an aspect ratio of the structures is within a range of 0.6 or more and 5 or less, wherein the aspect ratio of a structure is the ratio between an height of the structure and an average arrangement pitch, characterized in that a crosslink density of the structures is 0.8 mol/L or more and 5.1 mol/L or less, an average molecular weight between crosslinks of the structures is 700 or more and 1500 or less, and the structures contain, as a main component, at least one of an oligomer having two (meth)acryloyl groups and an oligomer having three (meth)acryloyl groups, wherein the average molecular weight between crosslinks of the resin material contained in the structures is a value obtained by dividing the average molecular weight of the resin material involved in a polymerization reaction by the average number of functional group when the resin material involved in a polymerization reaction has three or more functional groups or, when the resin material involved in a polymerization reaction has two functional groups, the average molecular weight between crosslinks is the average molecular weight of the resin material. a base material having a surface; and a plurality of structures which are arranged on the surface of the base material at a fine pitch equal to or shorter than the wavelength of visible light and which each comprise a convex or concave portion, wherein an elastic modulus of a material forming the structures is 1 MPa or more and 1200 MPa or less, the surface on which the structures are formed is hydrophilic, in that a water contact angle on the surface on which the structures are formed is 30° or less, and an aspect ratio of the structures is within a range of 0.6 or more and 5 or less, wherein the aspect ratio of a structure is the ratio between an height of the structure and an average arrangement pitch, characterized in that a crosslink density of the structures is 0.8 mol/L or more and 5.1 mol/L or less, an average molecular weight between crosslinks of the structures is 700 or more and 1500 or less, and the structures contain, as a main component, at least one of an oligomer having two (meth)acryloyl groups and an oligomer having three (meth)acryloyl groups, wherein the average molecular weight between crosslinks of the resin material contained in the structures is a value obtained by dividing the average molecular weight of the resin material involved in a polymerization reaction by the average number of functional group when the resin material involved in a polymerization reaction has three or more functional groups or, when the resin material involved in a polymerization reaction has two functional groups, the average molecular weight between crosslinks is the average molecular weight of the resin material.