When two stitch lines parallel with the hem of a workpiece are stitched by a multi-needle sewing machine, a thread feeding apparatus positively feeds threads to each needle in proportion to the radius of the stitch line curvature such that well-balanced stitch lines are performed. Sensors located adjacent to said needles, and CPU (Central Processing Unit) operate cooperatively to drive each stepping motor which positively feeds the exactly required stitch length to each needle.