A drive device for positioning a sewing machine main shaft and driven by a positioning motor into a needle-up position when it is stopped for example, after the thread is cut comprises a removable drive lever member which has a tappet portion which engages wtih the shoulder of a cam which is mounted on the main shaft for rotation therewith. The drive lever is driven by a device such as a fluid pressure operated piston cylinder combination and when it moves the tappet engages the cam face and rotates the cam with the main shaft to a second position which is predetermined. The mechanism also includes a stop which is effected between a face of the cam and a lever member which is shifted by the drive lever to stop the backward movement of the cam with the main shaft at a precise second position.