PURPOSE: To improve the yield of material by forming many small holes in a metallic sheet by digging before rolling the sheet under tension.

CONSTITUTION: Many small holes are formed in a metallic sheet 1 by digging while passing it between a rubber roll 8 and a hole-digging roll 7 having many projections 6. The sheet 1 is successively rolled by passing it between a pair of rolling rolls 9 while providing a tension to the sheet 1. As a result, the burred pieces 5 are buried in the sheet 1, and a metallic sheet pierced with holes is obtained without causing material loss. The enlogation percentage of 37W38% is obtained by rolling further the sheet under tension, and the rolling rate is improved. By this method, the yield of material and the rolling efficiency are improved, and the manufacturing cost is reduced.