The invention provides a cable main insulating layer cutting device, which belongs to the technical field of electric power overhaul tools. The device comprises a fixed frame, a movable clamping frame, an adjusting mechanism and a chamfering cutter. The movable clamping frame capable of sliding relative to the fixed frame is arranged on the fixed frame. Afirst groove and a second groove which areoppositely formed are formed in the fixed frame and the movable clamping frame respectively. The first groove and the second groove form a containing hole used for containing a cable. According to thecable main insulating layer cutting device provided in the invention, the device is simple in structure and convenient in installation and clamping operation. The cutting work of the main insulatinglayer of a cable completed by the manufacturing personnel is effectively improved. The defects that the traditional manufacturing method excessively depends on the technical experience of the workingpersonnel, stripping and cutting are performed by using tools such as a hand saw and an electrician knife, the speed is low, the process is not standard, and the safe operation of the cable is influenced are effectively eliminated. The generated economic and social benefits are obvious.