Provided is an optical member having high strength, low reflection, and a high transmittance. The optical member includes: a transparent substrate; and a porous glass layer having a spinodal-type porous structure disposed on the transparent substrate, in which at least one of the average pore diameter of a pore formed in the porous glass layer and the average skeleton diameter of a skeleton of the porous glass layer is set so that the optical member has a transmittance of 50% or more in the wavelength region of 450 nm or more and 650 nm or less.