A method of controlling a spindle of a spinning machine in which the spindle is provided for each of a plurality of spindle stations, the method comprising the steps of: setting a target rotation speed and a target number of yarn breakages for each of a plurality of intervals, wherein a spinning period is divided into the plurality of intervals; detecting a number of yarn breakages for the plurality of spindle stations for each interval during the spinning period; calculating a difference between the number of yarn breakages and the target number of yarn breakages for each interval during the spinning period the method being characterized by comprising the steps of: classifying a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages for a predetermined number of intervals of the plurality of intervals up to a current interval depending on characteristics of the changing trend of the difference during the spinning period; changing the target spindle rotation speed applied to the next interval based on a result of calculation made in the step of calculating and a result of classification made in the step of classifying during the spinning period; and controlling the spindle rotation speed in the next interval based on a changed target spindle rotation speed changed in the step of changing during the spinning process. setting a target rotation speed and a target number of yarn breakages for each of a plurality of intervals, wherein a spinning period is divided into the plurality of intervals; detecting a number of yarn breakages for the plurality of spindle stations for each interval during the spinning period; calculating a difference between the number of yarn breakages and the target number of yarn breakages for each interval during the spinning period the method being characterized by comprising the steps of: classifying a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages for a predetermined number of intervals of the plurality of intervals up to a current interval depending on characteristics of the changing trend of the difference during the spinning period; changing the target spindle rotation speed applied to the next interval based on a result of calculation made in the step of calculating and a result of classification made in the step of classifying during the spinning period; and controlling the spindle rotation speed in the next interval based on a changed target spindle rotation speed changed in the step of changing during the spinning process. classifying a changing trend in the difference between the number of yarn breakages and the target number of yarn breakages for a predetermined number of intervals of the plurality of intervals up to a current interval depending on characteristics of the changing trend of the difference during the spinning period; changing the target spindle rotation speed applied to the next interval based on a result of calculation made in the step of calculating and a result of classification made in the step of classifying during the spinning period; and controlling the spindle rotation speed in the next interval based on a changed target spindle rotation speed changed in the step of changing during the spinning process.