A method of producing a packaging material including a temporary bonding which temporarily bonds a first sheet including a thermoplastic resin non-oriented film layer and a thermoplastic adhesive resin layer laminated on one surface of the thermoplastic resin non-oriented film layer and a second sheet including a heat resistant resin oriented film layer and an aluminum foil layer laminated on one surface of the heat resistant resin oriented film layer by passing the first and second sheets between a pair of rolls in a state in which the thermoplastic adhesive resin layer and the aluminum foil layer are brought into contact with each other to press them while heating in a state in which the thermoplastic adhesive resin does not melt to obtain a pre-laminated sheet, and a complete bonding which integrally bonds the first and second sheets by heating the pre-laminated sheet to melt the thermoplastic adhesive resin.