PURPOSE: To provide a fluid-actuated impact hammer capable of being used for advancing an object into the ground and extracting it without requiring switching work at all.

CONSTITUTION: This impact hammer is provided with a working piston 22 movable within a working cylinder 21 and controlled by control means 40, 41 to exert impacts onto an anvil surface 23 of an adapter 24 which can be connected to the object to be advanced. When retracting the object, a return impact piston 51 exerts impacts onto the adapter 24 in the opposite direction, thereby the object can be better released from a drill hole.