The bar is allowed only axial motion and compressed to a running plate with constant velocity by a spring. If the bar is inclined with an angle less than frictionai angle between normal of the plate, then the bar repeats a jumping motion. That the motives of this motion are like a deflection by a friction is confirmed by experiments. In this paper, the motives of the jumping motion of the bar are analytically examined, and the some conditions of generation of the motion are obtained.