Process for producing substrate sheet for information recording mediums

A process for producing a substrate sheet for an information recording medium, having a preformat pattern with a length A and a width B, which comprise the steps of:

• melt-extruding a resin sheet;
• and
• passing the extruded resin sheet between a roll stamper, having on its periphery a pattern to be transferred corresponding to the preformat pattern, and a roll disposed opposite to the roll stamper, to transfer the pattern to be transferred to the extruded resin sheet,
• wherein the pattern to be transferred has a length a corresponding to the length A in the rotational direction of the roll stamper and a width b corresponding to the width B in a direction parallel to the axis of the roll stamper, the value of b/a being larger than the value of B/A.