To introduce even a narrow stringlike scrap cut off by a trimmer to a scrap treating equipment by naturally guiding to a guide chute by arranging a trimming device in a strip path inclined by a specific angle to a vertical line.

A trimming device is arranged in a strip path inclined by 30 to 45 degrees to a vertical line. As a result, a string-like scrap cut off by a trimmer falls in the direction of (2d to 2f), and naturally enters a guide chute 4. A disk-shaped upper cutter 3a and a lower cutter 3b of the trimming device are also arranged so that the outlet side becomes wider by 1 to 3 degrees than the inlet side in the advancing direction of a strip. As a result, the string-like scrap 2 cut off by the trimmer falls in the direction for separating from a strip main body.