To efficiently convert vibration energy of an exciter into concrete placing energy by fixing the hydraulic exiter which vibrates a table freely rockingly fitted to a supporting member to both ends in the oscillating direction of the table, driving and controlling the hydraulic exciter.

A table 2 is supported on a trestle 7 through a supporting member 3. A stopper 6 having a spring 19 is provided on the trestle 7 and the same hydraulic exiters 5a, 5b are provided on both sides of the table 2. In this case, a valve 14 and a sprue piston 12 having diameters D1-D6 are held in the inside of a piston cylinder 8. The annular groove of an inner wall, a flow path and a chamber are formed. Furthermore, a high pressure port P is communicated with chambers (a), (e) through a flow path 9. A low pressure port T is communicated with chambers (b), (g) through a flow path 10. A chamber (f) is communicated with a chamber (c) through a flow path 11. A valve 14 is formed in a pressure chamber (k) of the lower part. The sprue piston 12 beats a backing plate 15 through an auxiliary piston 13 to exite the table 2. Noise is prevented by uncompressed viscous fluid in a chamber (m). Therefore, vibration energy of the exciters 5a, 5b is efficiently utilized for concrete placing energy.