An antireflection structure (10) comprises a base (1), and a finely roughened antireflection part (2) formed in a surface of the base (1). The finely roughened antireflection part (2) includes a plurality of projections and depressions defined by the projections. The projections are distributed such that PMAX≦λMIN, where PMAX is the biggest one of distances between tips (2t) of the adjacent projections and λMIN is the shortest one of wavelengths of visible light rays in a vacuum. The sectional area of each projection in a plane parallel to the surface of the base (1) increases continuously from the tip (2t) toward the bottom (2b) of the depression adjacent to the projection. The shape (2Mt) of a tip part (Mt) of each projection in a plane perpendicular to the surface of the base (1) is sharper than the shape (2Mb) of a bottom part (Mb) of each depression in the same plane vertical to the surface of the base (1).