A breaking hammer comprising: a percussion device; a tool connectable to the percussion device; a sealing housing, which is located around the tool; a seal, which is located in the sealing housing; wherein the seal is a sleeve-like piece having an inner periphery, an outer periphery and an axial length; the inner periphery of the seal comprises a tool opening (21, 22) provided with sealing surfaces, which are intended to be arranged to face towards the tool to be sealed; and the outer periphery of the seal is provided with fastening surfaces for fastening the seal to a body of the breaking hammer; characterized in that the seal has two-part configuration and comprises a first seal element and a second seal element which are arranged successively in axial direction; the mentioned fastening surfaces are located on the outer periphery of the first seal element; the second seal element is fastened only to the first seal element, whereby it is without fastening surfaces for fastening it to the body of the breaking hammer; the first seal element is made of resilient material and comprises a first tool opening which is intended to be in resilient contacting relationship with the tool; the second seal element is a rigid element and comprises a second tool opening, which is dimensioned to form a sealing clearance between the tool and the second seal element; diameter of the first tool opening is smaller than diameter of the second tool opening; and the resilient first seal element of the seal allows the rigid second seal element to move transversally together with the tool relative to the sealing housing. a percussion device; a tool connectable to the percussion device; a sealing housing, which is located around the tool; a seal, which is located in the sealing housing; wherein the seal is a sleeve-like piece having an inner periphery, an outer periphery and an axial length; the inner periphery of the seal comprises a tool opening (21, 22) provided with sealing surfaces, which are intended to be arranged to face towards the tool to be sealed; and the outer periphery of the seal is provided with fastening surfaces for fastening the seal to a body of the breaking hammer; characterized in that the seal has two-part configuration and comprises a first seal element and a second seal element which are arranged successively in axial direction; the mentioned fastening surfaces are located on the outer periphery of the first seal element; the second seal element is fastened only to the first seal element, whereby it is without fastening surfaces for fastening it to the body of the breaking hammer; the first seal element is made of resilient material and comprises a first tool opening which is intended to be in resilient contacting relationship with the tool; the second seal element is a rigid element and comprises a second tool opening, which is dimensioned to form a sealing clearance between the tool and the second seal element; diameter of the first tool opening is smaller than diameter of the second tool opening; and the resilient first seal element of the seal allows the rigid second seal element to move transversally together with the tool relative to the sealing housing.