A phase change memory capable of highly reliable operations is provided. According to the present invention, retinol derivatives comprise carboester linkage between di-, tri-, polypeptide having functional group of COOH and retinol. The fruit matures under the ecological conditions described during mid August, with first picking on Aug. Thus, an operational efficiency is greatly improved. The method for manufacturing an optical element further includes bonding the first face side of the first translucency member to the second face side of the second translucency member by an adhesive layer.