An antireflection film 3 provided on an optical substrate 2 of an optical member 1 has a reflectivity adjusting film 4 including a first layer 10, a second layer 11 having a refractive index higher than a refractive index of the first layer 10, a third layer 12 having a refractive index lower than a refractive index of the second layer 11, and a photocatalyst film 5 including one or more photocatalytically active layers 14 containing titanium dioxide, in which a thickness of the reflectivity adjusting film measured from a surface 4a is equal to or greater than 20 nm and less than 150 nm, the photocatalyst film 5 is provided between the reflectivity adjusting film 4 and the optical substrate 2, an interface 5a between the photocatalyst film 5 and the reflectivity adjusting film is disposed at position spaced apart from the surface 4a by a distance equal to or shorter than 150 nm, and a total thickness of the photocatalytically active layers 14 is equal to or greater than 350 nm and equal to or smaller than 1,000 nm.