In a broadening course, a yarn feeder of which front and back agree with the front and back of a fabric is used as a preceding yarn feeder, and a yarn feeder of which front and back are reverse is used as the succeeding yarn feeder,(a) the preceding first yarn feeder is used to knit the first fabric, and to newly feed yarn to needles of the opposing needle bed on the lower side of the knitting direction of the course, and to needles of the original needle bed, and(b) the succeeding yarn feeder is used to knit the first fabric, and to feed yarn again to either one of needles to which yarn was newly fed by the first yarn feeder in the above-mentioned step a.