To provide a roll up protective device in which a wave is not formed by a belt at least partially made of steel, irrespective of a total surface of a flat surface.

Embossing processing is executed by using a pair of embossing rollers. Specifically, the embossing processing is executed by using: a roller 13 rotating around a center shaft 14 and having a plurality of punches 15 on its outer edge in parallel to the shaft 14; and a counter roller 16 made of elastic material and rotating around a shaft 17 parallel to the shaft 14. In a process of making the belt 5 pass between the roller 13 and the counter roller 16 so that a right angle is formed by a side edge 12 of the belt 5 and shafts 14, 17, a surface layer 10 formed of steel is periodically brought into contact with the punch 15, while the surface layer 11 formed of fabric or plastic material is continuously brought into contact with the counter roller 16, and thereby the punch 15 is wound and locally bent.