To provide a low noise type abrasion-resistant hydraulic hammer improved to prevent the leak-out of noise generated inside the hydraulic hammer.

A sound insulating member containing oil is provided in a hole formed outward under a piston 1 elevatingly provided inside a body 4 of a hydraulic hammer 10, so as to guide a tool 3 while being in contact with the peripheral surface of the tool 3. Impulsive sound leaking out of the hydraulic hammer is therefore reduced to provide comfortable working environment and to meet environmental standards against noise.