Disclosed is an automatic top mat supplying device having a cutting failure prevention function. The main features of the disclosed apparatus include a conveying conveyor for conveying seedlings； An unwinding roll rotatably provided on an upper side of the conveying conveyor, the top mat being wound in a roll state； A top soil mat supply unit which serves to transfer the top soil mat from the unwinding roll to a seedling plate conveyed by the transfer conveyor, and includes a top transfer roll and a middle transfer roll each consisting of upper and lower rolls； A top soil mat cutting unit for cutting the top soil mat between the upper transfer roll and the middle transfer roll； And a controller for controlling the on / off operation of the top mat supply unit and the top mat cutting unit, wherein the upper and lower rolls of the upper feed roll and the middle feed roll are connected to each other by gears in opposite directions. Is rotated, the lower axis roll of the upper feed roll and the middle feed roll is connected to each other by a timing pulley and the timing belt to be linked to rotate, but the middle feed roll side timing pulley is faster than the upper feed roll side timing pulley to cut the cutting poor It further comprises preventing the phenomenon, and further comprises an unwinding roll stopping unit disposed between the unwinding roll and the top mat supply unit to selectively stop the unwinding roll, wherein the unwinding roll stopping The unit may include a rotatable bracket in the form of the rotatable bar； A return spring elastically supporting the rotation bracket to return to its original state； First and second guide rollers rotatably installed at both ends of the rotating bracket, and the top and bottom mats released from the unwinding roll are wound in a zigzag shape； A stopping bar having one end pin-coupled to the rotation bracket to selectively stop the unwinding roll while moving forward and backward toward the center of the unwinding ro
