To remedy defects of prior arts by ensuring corrective operations to be conducted accurately and automatically.

This method comprises setting and storing knitting data of a knitted fabric sample, placing a knitted fabric 2 after knitted in position, photographing the form of the knitted fabric with a camera 4, gripping two or more positioning points of the knitted fabric 2 with a gripping means 5 on the basis of the above-photographed knitted fabric image, calculating and outputting the respective corrections of the positioning points of the knitted fabric 2 in an image processing unit from the stored knitting data and photographed knitted fabric image, moving the gripping means 5 according to the output so that the corrections are reduced to a criterion or below, thus correcting deformation of the knitted fabric 3, then moving the gripping means to a steam set position by a conveying means 8 while holding the corrected condition with a form-holding means 15, and making a steam-forming of the knitted fabric 2 by a steam set means 18.