PURPOSE: To produce a sliding plate for a sill fitting section having excellent sliding automatically at low cost by a method wherein a pattern is formed on an extrusion-molded synthetic resin sheet, a double-sided adhesive tape with release paper is stuck, a cutting plane line is drawn and the sheet is cut.

CONSTITUTION: A sliding plate stuck on the base of the sill fitting section of a building is manufactured by the following process. A raw resin is extruded from a mold 65 for an extruder 60, and passed between rolls 62, 63, and a long-sized plate 66, to which an irregular pattern meandering in the longitudinal direction is notched and which has fixed width and fixed thickness, is manufactured, and wound by a winding machine 68. A long-sized plate 66 is drawn after cooling, and a double-sided adhesive sheet 71 with release paper 71a is superposed on a rear, and passed between rolls 72, 72 and pasted. One end of release paper 71a is peeled and passed on a support far 73, cutting plane lines in the longitudinal direction are drawn on both surfaces of the long-sized plate 66 with the double-sided adhesive sheet at regular intervals by a slitter 74, and release paper 71a is stuck again by a roller 76, and the long-sized plate 66 is cut in specified length by a cutter 77. The insides of the recessed grooves of the pattern are coated with paraffin and wax, thus reducing friction.