A sewing machine includes a sewing machine motor serving as a drive source for driving the vertical movement of a needle bar, a control part for controlling the sewing machine motor such that a sewing pitch coincides with a set value, and imaging part for imaging a seam formed in a workpiece at a needle drop position. The control part obtains the length of the most recent seam from an image of the most recent seam imaged by the imaging part and also compares the length of the most recent seam with the set value of the sewing pitch to thereby correct the number of rotations of the sewing machine motor.