The invention discloses a material shortage monitoring device of an automatic wire guide machine for electric welding. The material shortage monitoring device comprises a sensor used for detecting whether a metal wire exists or not, and the sensor directly faces the metal wire. The outer side of the sensor is provided with a thread and is further sleeved with two gland nuts. A flexible metal bar wound on the sensor is clamped between the two gland nuts. The flexible metal bar is fixed to the wire guide machine. A signal line of the sensor is connected with a PLC, and the PLC is connected with a driving device used for controlling a metal wire material wheel to achieve feeding. By means of the material shortage monitoring device, metal wire shortage monitoring can be achieved, and the automatic wire guide machine for electric welding can be interrupted during material shortage to feed wires to the welding position continuously.