The invention relates to the technical field of welding robots and provides a servo wire feeding device for an automatic welding robot. The servo wire feeding device has a good insulation effect and has functions of dust prevention and chip prevention. The servo wire feeding device comprises a servo wire feeding welding gun body and a linear buffer connected with the tail end of the servo wire feeding welding gun body through a conducting wire cable. The servo wire feeding welding gun body comprises a welding gun shell, a gun nozzle assembly mounted on the front side of the welding gun shell, servo wire feeding motors, wire feeding wheels and a bottom flange, the servo wire feeding motors and the wire feeding wheels are installed in the welding gun shell through a sky beam and a wire drawing base, and the bottom flange is installed on the rear side of the welding gun shell; insulation structures are arranged between the servo wire feeding motors and the wire drawing base, between the wire feeding wheels and the servo wire feeding motors, between the sky beam and the bottom flange, between the wire drawing base and a front flange support, and between a lower housing and the wire drawing base; key groove connecting structures are arranged between the servo wire feeding motors and a wire wheel locating sleeve, and between the wire wheel locating sleeve and the wire feeding wheels; dust prevention structures are arranged between the wire feeding wheels and the wire feeding motors, between the sky beam and the bottom flange, and between the wire feeding motors and the wire drawing base.