PURPOSE: To effectively absorb the pulsation pressure of wide-ranged frequency with a small space and at a low cost by incorporating a Helmholtz resonator which is a passive pulsation pressure generating means, into an active pulsation pressure generating means where a piezoelectric element is used for reducing pulsation pressure. source 1 on one end and a load on the

CONSTITUTION: A pulsation pressure source 1 on one end and a load on the other end are connected to each other by a fluid pressure circuit 2. A pulsation pressure generating means 4 which generates fluid pulsation pressure by applying voltage to a piezoelectric element 3 is disposed in the mid of the fluid pressure circuit 2. A Helmholtz resonator 6 whose resonant frequency is set to the maximum response frequency of the piezoelectric element 3 or more is disposed at the pulsation pressure generating means 4 by volume chambers 6a, 6b where fluid volume changes with strokes of a piston 5 disposed at the top end of the piezoelectric element 3. A pulsation pressure absorbing control means 8 which controls voltage applied to the piezoelectric element 3 is disposed to eliminate fluid pulsation pressure from the pulsation pressure source 1.