A method of manufacturing a packing paper is provided to manufacture various kinds of packing papers at low cost by printing an outer paper of the packing paper with an offset printing method and separately forming the outer and inner papers of the packing paper. A method of manufacturing a packing paper includes the steps of: supplying an outer paper from an outer paper feeder to an outer paper conveyor belt(S1); punching a hole on the outer paper by a puncher(S2); applying an adhesive on a circumference of the punched hole(S3); attaching a film sheet to the applied adhesive after cutting the film sheet wound on a roll(S4); applying the adhesive on the outer paper while moving in the width direction(S5); applying the adhesive on inner papers transferred by an inner paper conveyor belt(S6); bonding the inner papers transferred by a combined conveyor belt(S7); punching a hole on the bonded inner papers in correspondence to the hole punched in the second step(S8); bonding the outer and inner papers so that the holes formed on the outer and inner papers correspond to each other and the outer paper is placed under the inner paper(S9); applying the adhesive on one of both sides of the bonded paper while applying the adhesive on a predetermined width of the outer and inner papers(S10); and folding both lateral ends of the bonded paper to overlap with each other in the shape of a tube in which the outer paper is placed on the outer surface of the bonded paper and the inner paper is placed on the inner surface of the bonded paper and forming both side surfaces of the tube with a gusset(S11).