the center part of the needle swinging range and the needle swing driving device bd positions the needle at the center position concurrently the and circuit and becomes h level and the needle dropping hole changing device n is operated to provide a reduced circular needle dropping hole the change of the needle dropping hole is made when the displacement of the needle has been separately detected then if the automatic manual changing switch s8 for the needle lateral swinging control is once pushed the flip flop ff1 is reset and the needle dropping hole changing device n provides the laterally elongated needle dropping hole the group of and or circuits and or1 makes operative the digitalized value of the manually controlled value by operation of the variable resistor vr1 to provide the input k1 of the arithmetic unit au1 when the resistance of variable resistor vr1 is set at the minimum value the decimal number k 39 1 is 0 and 34 0 30 0 30 0 0 34 is provided by the formula of k 39 1 g 39 b k 39 2 30 k 39 2 and the needle position is designated at a point maximum in the leftward direction similarly when the resistance is set at the maximum value the decimal number k 39 1 is 30 and 34 30 30 0 30 0 30 34 is provided and the needle position.