To recover kinetic energy effectively and recycle the energy even if an inertial object is forced to stop moving beyond its movable range.

When either of rods 6a, 6b of a shock absorber 6 which is fixed on both sides of a load carriage is brought into contact with a stopper block, hydraulic fluid in a cylinder chamber 6f is compressed against energizing force of compressive coil spring 6e. When the pressure exceeds accumulated pressure in an accumulator 3, a flow is generated from the cylinder chamber 6f to the pressure storing device 3 through the first check valve 7, the kinetic energy of the load carriage is recovered in the accumulator 3. As a result, it can be recycled as driving force in the next process, and shock at the time of stopping is relieved. When the load carriage 1 moves in the opposite direction, the rods 6a, 6b are pushed out, and hydraulic fluid in a reservoir tank 4 flows into a shock absorber 6 through the second check valve 8.