PURPOSE: To effect a captioned embossing easily at any desired position by a method wherein a recess and protrusion forming mold is put on the surface of a hollow body formed by extrusion molding when the body is still in a softened condition, thereafter, the mold is pressed and cooled.

CONSTITUTION: A hollow body 2 is molded by extrusion continuously by an extrusion molding machine 1. Subsequently, a recess and protrusion forming mold 3 is put on a surface of the hollow body 2 when it is still in a softened condition. Then, a portion of the hollow body where the recess and protrusion forming mold 3 is put is pressed to an upper portion of an inner wall of a die 4 in the vacuum sizing die 4 and the recess and protrusion forming mold 3 is bitten into the hollow body 2. Thereafter, the hollow body 2 is cooled and then the recess and protrusion forming mold 3 is removed to obtain the hollow body 2 having an embossed pattern 9. The embossed patterns may be embossed easily at any desired place discontinuously.