1. An embroidery data producing device producing embroidery data on which an embroidery sewing machine forms an embroidery pattern along another pattern previously formed on cloth held by a cloth holding frame, the device comprising: image data producing means for scanning the cloth held by the cloth holding frame to produce pattern image data corresponding to the pattern; and embroidery data producing means for producing embroidery data for forming an embroidery pattern on at least a part of the pattern on the basis of the pattern image data, the embroidery pattern having a size equal to that of the pattern.