Saw blade device of combined rock breaking tool bit

The invention discloses a saw blade device of a combined rock breaking tool bit. The saw blade device comprises a saw blade structure and a saw blade driving device, wherein the saw blade structure and the saw blade driving device are installed on a lower box body; the saw blade structure comprises a short shaft saw blade and a long shaft saw blade; the short shaft saw blade comprises a short shaft, a bearing, a bearing end cover, a circlip for shaft, a sealing felt, an inner oil thrower, an inner clamping cutter disc, a diamond saw blade a, an intermediate sleeve cutter disc, a diamond saw blade b, an outer clamping cutter disc, a screw, a flat gasket and an elastic gasket; the long shaft saw blade and a short shaft shoulder can be interchanged by increasing or decreasing the length of ashaft; the saw blade driving device comprises a motor, a fixing bolt and a diaphragm coupler; the saw blade structure is connected with a motor through the diaphragm coupler; and the motor is mountedon a lower box body throug