To provide an optical filter that has an inorganic hard film formed on a transparent resin substrate, is superior in heat resistance and environmental resistance, and can meet higher picture quality.

In an optical filter, on a transparent resin substrate 20, an inorganic hard film including an ND film 31 composed of at least a dielectric film is formed, so that a transmitted light volume is controlled, and the glass transition temperature of the transparent resin substrate 20 is made 200°C or more, and the absolute value of photoelastic coefficient C of the transparent resin substrate 20 is made smaller than 50×10^-12 Pa^-1.