The invention discloses an automatic adhesive tape machine, which comprises a transmission switching mechanism, a cutting mechanism, a transmission mechanism, a conveying mechanism and a cutting control mechanism. The transmission switching mechanism and the cutting mechanism are arranged inside an upper shell; the transmission mechanism, the conveying mechanism and the cutting control mechanism are arranged inside a lower shell; and the inner wall of the lower shell is provided with a supporting shaft for fixing the upper shell to make the upper shell assembled in the lower shell and rotate around the supporting shaft. The automatic adhesive tape machine drives twin linked gears through a spring and a key in the transmission mechanism, and the twin linked gears drive racks so as to drivethe conveying mechanism, the cutting control mechanism, the transmission switching mechanism, and a blade moving mechanism to execute corresponding actions in sequence through the racks and finally output and cut off adhesive tapes. The automatic adhesive tape machine has the functions that: a, the adhesive tapes can be automatically sent out by certain length when the key is pressed; b, the adhesive tapes can be pulled out limitlessly if the key is continuously pressed; and c, the adhesive tapes can be cut off by a blade when the key is loosened. The automatic adhesive tape machine has the advantages of reasonable structure, stable performance, easy operation and the like.