PURPOSE: To provide a walking bar device of a sewing machine in which the horizontal cloth feed of a walking bar feed dog is not changed by a change of thickness of a cloth to be worked.

CONSTITUTION: A walking bar device comprises a walking bar horizontal driving means including an oscillating member 1, a guide rod 2, and a first vertical rod 5, a walking bar feed dog 50, a cloth thickness detecting means 68 and horizontal cloth feed changing means. The thickness (w) of a cloth W to be worked is detected by a cloth thickness detecting means 68, and according to the thickness (w) of the cloth, the horizontal cloth feed of the walking bar feed dog 50 is set by the horizontal cloth feed changing means. Thus, regardless of the thickness (w) of the cloth W to be worked, the horizontal cloth feed is obtained by the walking bar feed dog 50.