The present invention aims to variably set control conditions for avoiding a hitch stitch. By a program executed by a CPU (101), a determination is made as to whether a direction in which a next stitch is to be formed belongs to a predetermined area corresponding to a hitch stitch, and upon determination that the direction in which the next stitch is to be formed belongs to the predetermined area, detour control is performed which includes moving a holding member (5), holding a sewing workpiece, so as to detuor an upper thread, extending downward from a sewing needle, in a direction corresponding to a perfect stitch and then further moving the holding member to a target position corresponding to the next stitch. Various conditions for the detour control are variably set via an operation panel (6) and a program executed by the CPU (101) (setting means). Such variable setting can be done by user's operations via the operation panel (6), by setting detour-controlling data incorporated in sewing pattern program data, and/or the like. The conditions for the detour control include enabling execution of the detour control and variably setting a range of the predetermined area.