An optical substrate includes a transparent substrate; an interference spot-preventing layer composed of at least one sublayer, the interference spot-preventing layer being coated on the transparent substrate; and a hard coat layer disposed on the interference spot-preventing layer. In the optical substrate, when the complex refractive index of the hard coat layer at light of 550 nm is represented as nH−ik, nH is 1.45 to 1.59 and k is substantially zero. When the optical admittance of the interface between the interference spot-preventing layer and the hard coat layer is represented as (x+iy), x and y satisfy the formula of (x−nH)2+y2≦0.08.