The invention belongs to the technical field of auxiliary equipment of a machine tool, and relates to a lighting device of a machine tool. The machine tool comprises a machine tool body, a machine tool head box arranged on the machine tool body and a workpiece machining box body. The machine tool head box is arranged on the right side of the workpiece machining box body. Shielding doors shielding a work cavity of the workpiece machining box body are assembled on the workpiece machining box body. A lighting device is a lamp band. The lamp band is arranged on the top in the length direction of the work cavity. Due to the fact that the lamp band is adopted and arranged on the top in the length direction of the work cavity, the lighting area can be obviously expanded, the lighting dead angle is eliminated, and an operator can conveniently clamp a workpiece and observe the machining situation of the workpiece in the work cavity outside the shielding doors. Due to the fact that the lamp band is adopted, the structure can be greatly simplified, space is saved, and installation is convenient; and due to the fact that the LED lamp band has the superior brightness and is low in power consumption, the electric energy consumption can be reduced easily.