To improve the response characteristics of a shaker by controlling resonance frequencies caused by the compressibitity of a working fluid inside the shaker.

The acceleration of a shaker piston 7A is detected, and the amount of correction of a locational function of the piston is computed by counters 12, 13, and 15 and an integrator 13. This amount is added to the amount proportional to the speed of the shaker piston by an adder 22, and this is added to the adder 19 of a servo amplifying part 4. In this way, resonance frequencies caused by the compressiblity of a working fluid inside a shaker are attenuated, and it is possible to use the shaker in a wide oscillation frequency range.