The invention discloses a full-automatic cutting-off machine. The full-automatic cutting-off machine comprises a machine table, a power device, a feeding device, a material receiving device, a head trimming device and a clamping and cutting-off device, the power device, the feeding device, the material receiving device, the head trimming device and the clamping and cutting-off device are installed on the machine table, and the feeding device, the material receiving device, the head trimming device and the clamping and cutting-off device are separately connected with the power device; the feeding device comprises a material tray, a driven shaft, a material trimming wheel installed on the driven shaft, a rotating shaft, a feeding wheel installed on the rotating shaft, a driving belt for connecting the driven shaft with the rotating shaft, a ratchet wheel installed at one end of the rotating shaft, a driving rod connected with the power device and a pawl installed at the free end of the driving rod; the power device drives the driving rod to move in a back and forth reciprocating mode so as to drive the feeding wheel and the material trimming wheel to rotate, and the feeding wheel is used for conveying workpieces in the material tray to the material receiving device. According to the full-automatic cutting-off machine, the feeding device, the material receiving device, the head trimming device and the clamping and cutting-off device are simultaneously driven by the power device to automatically complete all actions, manual processing is not needed, the processing efficiency is high, and the full-automatic cutting-off machine is safe and reliable.