To provide an optical element which has an optically functional surface, the normal direction of which forms a high angle with the optical axis direction of the optical element, and on the optically functional surface of which a biased distribution of the reflectances of the lights entering from various directions is alleviated.

In the optical element 1, a plurality of projecting parts 3a constituting a minute structure 3, which is formed in a region of a highly inclined part 2 whose normal direction 5 forms the high angle with the optical axis direction of the optical element, are formed so that a formed direction 4 of the projecting part 3a forms an inclined angle 6 with the normal direction 5 of a curved surface 1a (the optically functional surface) in a formed position of the projecting part 3a. As a result, the biased distribution of the reflectances in the highly inclined part 2 and other regions on the curved surface 1a is alleviated so that an excellent antireflection effect can be obtained in the whole region of the curved surface 1a of the optical element 1.