A needle bar stopper is provided in a sewing machine having a main shaft and a needle bar which moves vertically upon reception of a driving force from the main shaft. The needle bar stopper comprises a transmission prohibiting unit, including a needle bar stopping solenoid, which prohibits transmission of the driving force from the main shaft to the needle bar and a braking unit, including a needle bar stopping solenoid, which applies a braking force to the needle bar when transmission of the driving force is prohibited by the transmission prohibiting unit. The needle bar stopper can stop the needle bar reliably by use of the braking unit.