The present invention was made to improve the strength, such as heat resistance, of a disc comprising a biodegradable resin. The optical disc according to the present invention is formed by bonding two substrates, at least one of the substrates having an information recording area. One substrate disposed on a light incident side of the optical disc is composed of a biodegradable resin that is uncrystallized and allows light to transmit therethrough. Another substrate disposed away from the light incident side of the optical disc is composed of the biodegradable resin having higher crystallinity than that of the substrate disposed on a light incident side of the optical disc.