The invention discloses an automatic vending machine and a bag spitting device thereof, and relates to the field of vending machines. The automatic vending machine comprises a bag rolling-up shaft, aclamping mechanism, a bag output mechanism and a control unit which are arranged in the vending machine, wherein plastic bags or paper bag rolls are sleeved on the bag rolling-up shaft, the outermostplastic bag or paper bag of the plastic bags or paper bag rolls penetrates through the clamping mechanism and then stretches into the bag output mechanism, the control unit controls the clamping mechanism to loosen the clamped plastic bag or paper bag after receiving a bag taking signal and controls the bag output mechanism to send needed quantity of plastic bags or paper bags to a plastic bag orpaper bag outlet in the vending machine, and after the bag output mechanism completes the bag outlet operation, the control unit controls the clamping mechanism to clamp the plastic bag or paper bag penetrating therein. The automatic vending machine and the bag spitting device thereof can prevent people from pulling plastic bags or paper bags randomly, so as to improve the plastic bag or paper bagutilization efficiency of the vending machine and save the good selling cost.