PURPOSE: To execute a batch processing in large quantities by sticking and fixing a reflection film protective plate which has been manufactured by a pressing or molding, to an information recording medium.
CONSTITUTION: A sheet-shaped protective plate 1 consisting of a resin having a linear expansion coefficient being equivalent to that of an information recording medium is manufactured by blanking it by a press or by injection molding. As for thickness of the protective plate 1, ≥0.3mm is enough. Subsequently, an information recording medium 3 provided with a guide use slanting face 3 of the protective plate 1 is formed, and this guide slanting face 2 is provided in order to allow the protective plate 1 to adhere closely to the information recording medium 3 even if a variance of the outside diameter dimension of about ±1mm exists in the protective plate 1. Next, the protective plate 1 is placed on along the guide use slanting face of the information recording medium 3, and fixed by executing heat caulking to several parts by a heater 4 or an ultrasonic wave. In such a way, any process is suitable for mass production, and can cope with manufacture of a monthly production of scores of hundred thousand pieces.