The AB-1351 has adopted, as its operation panel, the IP-420 which has operation panel, the IP-420 which has a large color liquid crystal touch panel. With this operation panel, the operator can change the belt-loop shape or sewing pattern, set the belt-loop sewing position and carry out cycle sewing. When the belt-loop width is changed, the bartacking width is changed, the bartacking width can be automatically changed according to the precentage of change of the belt-loop width. Digitalization helps substantially reduce the time required for sewnig data adjustment.