PURPOSE: To perform embroidery faithful to a mosaic original picture by calculating the sewing order and needle-sticking points of respective sewing lines constituting a pattern by means of a CPU.

CONSTITUTION: An original picture is taken in by means of a CPU via an image scanner 2, and making an ON-mosaic unit of an embroidering region. Pattern lines are applied to form a sewing pattern being the locus of sewing thread, so that the pattern lines being the relevant segments are applied. All the pattern lines and terminal points are classified into either intersecting points or branch points, and making an intersecting point of the points where a pair of pattern lines are straightforwardly connected. The intersecting points including this intersecting point and branch points maintain an adjoining relationship via pattern lines or sewing lines. A series of pattern lines being dividedly connected at the branch points and straightforwardly connected at the intersecting points, or the sets of a series of sewing lines are made the same group. Making the connecting points of the sewing line between different groups intersecting at intersecting points. the sewing line is followed up while retrieving and selecting the sewing line of groups at the intersecting points.