A gore as a portion of a continuous elongated knitted fabric in a wale direction like a flared skirt is used. A knitted fabric formed by connecting a plurality of the gores in a course direction is designed. At the time of designing a pattern spread over a plurality of gores, the pattern is designed on the outer shape image as a composite image of the gores, and the design is divided into gores. At the time of assigning the pattern to the gores, it is checked whether any narrowing course is present in the pattern. If any narrowing course is present, on the upper side of the narrowing course, the left and right borders of the pattern are shifted toward the center of the knitted fabric, by the amount corresponding to the number of narrowing stitches from the center of the knitted fabric or the like.
