PURPOSE: To simply manufacture the above extrusion molded sheets of different width.

CONSTITUTION: Three protruding lines 2 are formed on the rear face of an extrusion molded sheet 1. Said protruding lines 2 are extended in the extrusion direction, and the disposing pitch of protruding lines 2 is 100mm. Protruding lines 4 of the size of half the protruding line 2 are foremd on the sides of the extrusion molded sheet 1. A cut body of 100, 200 or 300mm width by cutting said extrusion molded sheet 1 of 400mm width by means of a line A, B or C. When said cut bodies or extrusion molded sheets are bonded, sheets of many kinds of standard width dimensions such as 500, 600, 700mm... can be manufactured easily. It is, therefore, sufficiet to prepare a small number of extrusion dies in an extrusion molding machine, and the cost reduction and delivery period shortening can be realized in the case of manufacture of small quantities in many kinds of articles.