To manufacture a wide flange shape whose deviation of the web center is reduced by correcting the deviation of the web center, securely allowing it to fall within the target value and by comparatively simple and inexpensive constitution even in the case the direction of deviation is different in the right and left flanges at the time of manufacturing the wide flange shape.

The deviation of the web center of a material to be rolled is mesured with a web center deviation measuring device 7 which is installed on the inlet side, outlet side or in the intermediate position of a rolling mill group provided with roughing universal mill 3 (3-1, 3-2) and edger mill 4 and, in the case the direction of the deviation of this web center is different in the right and left flanges, by moving the edger rolls 4a, 4b of the edger mill 4 which is situated in front or in rear of the roughing universal mill 3 (3-1, 3-2) in the horizontal direction in accordance with the measured amount of deviation of the web center, executing rolling shifting the roll centers of the upper and lower edger rolls 4a, 4b and more greatly reducing the ends of flanges having longer leg length of the flange, the deviation of the web center whose direction is different in the right and left flanges is corrected.