An arrangement for mounting and supporting of a shank of a drilling machine comprising a body supported by a carriage, a percussion piston mounted in the body, and supporting housing positioned at a front side of the body, and a shank piece mounted in the supporting housing as an axial extension of the percussion piston. In order to reduce the strains exerted on tie rods of the body of the drilling machine, the supporting housing of the shank is supported at least partly by the carriage separately from a support between the body and the carriage so that the sideward forces acting on the shank are received directly by the carriage through the supporting housing.