String drawing device of string penetrating machine

A string drawing device of a string penetrating machine comprises a string clamping machine and is characterized by further comprising a transmission mechanism, a driving mechanism, a sensor and a control circuit. The sensor can sense tension force exerted on the string clamping machine and transmits a detected tension force value to the control circuit. The control circuit compares the detected tension force value with a set value and correspondingly issues instructions to enable the driving mechanism to be loosened, stopped or tightened, and therefore forward and backward movement of the string clamping machine is controlled. The string drawing device of the string penetrating machine achieves the fact that when tension force change, caused by string tensile deformation, of a tennis string (or a badminton string) occurs in a string drawing process, the tension force of the string can obtain dynamic compensation, and achieves accurate constant tension force string penetrating operation.