To easily and exactly adjust a damper pressure, without bending a damper wire by turning an adjusting screw loosely inserted from behind into the through-hole of a damper block, thereby regulating the damper pressure.

A through-hole 27 penetrating the damper block 15 in its longitudinal direction is formed at damper block and an adjusting screw 25 is inserted into the through-hole 27 from the behind. Internal screw threads 28 are formed at the damper block 15, and the adjusting screw 25 is screwed to these internal screw threads 28. A coil spring 26 has considerably large ridigity and is arranged between the damper block 15 and a damper head 16. The regulation of the damper pressure is executed by a method of treading a loud pedal to put all the dampers into a state of detaching the same from strings S all at once. When the adjusting screw 25 is turned in the stopped state of the damper head 16, the damper head 16 and damper felt 17 move in the longitudinal direction with respect to the damper block 15. Then, the spacing between the string S and the damper felt 17 is regulated to a prescribed value.