A method for producing a press molded body is provided in which a material X that contains a thermoplastic resin Rx and carbon fibers A having a weight average fiber length LwA and a material Y that contains a thermoplastic resin Ry and carbon fibers B having a weight average fiber length LwB are heated, and the heated material X and material Y are pressed within a mold at the same time, thereby producing a press molded body which has a region X that is formed of the material X and a region Y that is formed of the material Y. This method for producing a press molded body is configured such that: LwB