Abstract: A sewing machine is with stepper motors which work alternately in one direction or another to greatly reduce the number of parts for achieving the movement desired in the internal mechanisms of zig-zag sewing machines. The zig-zag mechanism for moving the sewing needle consists of a single, main driving element, formed by a stepper motor. The mechanism has a radial cogged spur gear at its outlet which engages a rack or linear gear formed by two adjoining bodies each having meshing teeth that engage the spur gear to eliminate any play between the spur gear and the two rack bodies. The rack is connected to a lever mechanism including an elongated, cambered,--shaped lever with a curved end. The curved end of the lever is connected to a needle bar support which is pivotally connected at its upper end to the sewing machine. A needle bar is connected to the needle bar support to enable the lever mechanism to impart a to and fro rocking motion to the needle.