A technique of an optical card having high information recording density. A specially superior writing characteristic is required for an additional recording optical card among optical cards. In the case where the optical card of additional recording type is closed, reduction in the writing characteristic is observed. In this invention, a sensitizing layer (50), which serves as escape for molten recording material at writing, is provided in rear of an optical recording section (30), so that an optical card is produced which is superior in both environmental resistance and writing ability. The sensitizing layer (50) is made of self-oxidizable or thermoplastic resin and an absorbing agent dispersed in the resin. The absorbing agent cooperates with the resin not only to improve a writing characteristic, but also to improve design ability and reading ability of the card.