A roll stamper used in a process of continuously forming a uniform sheet of a resin from which information recording medium bases are obtained. This roll stamper has a stamper member having in its surface a pattern corresponding to a pre-format pattern of an information recording medium, fixing members fixed on opposite end portions of a reverse surface of the stamper member so as to be integral with the stamper member, and a specular roll base having an engagement groove formed in its circumferential surface parallel to its axis. The stamper member is fixed on the specular roll base by fitting the fixing members in the engagement groove. A recess formed in a circumferential surface of the roll stamper as a gap between the fixing members is filled with a filler so that the roll stamper circumferential surface is substantially smooth. Side surfaces of the fixing members and/or the engagement groove are shaped as to suitably retain the filler.