A method for producing a foamed molded product, the method comprising: using a molding apparatus including a plasticizing cylinder having a high pressure kneading zone in which a molten resin, obtained by plasticizing a thermoplastic resin, is brought in contact and kneaded with a physical foaming agent, and a pressure reduction zone in which the gasified physical foaming agent is discharged from the molten resin brought in contact and kneaded with the physical foaming agent; and a screw arranged rotatably and movably back and forth in the plasticizing cylinder; plasticizing the thermoplastic resin to provide the molten resin; shutting off communication between the high pressure kneading zone and the pressure reduction zone; bringing in contact and kneading the molten resin with the physical foaming agent in a state that the communication between the high pressure kneading zone and the pressure reduction zone is shut off; controlling a pressure of the pressure reduction zone to be a first pressure in a state that the communication between the high pressure kneading zone and the pressure reduction zone is shut off, the first pressure being not less than an atmospheric pressure and not more than a maximum pressure of the high pressure kneading zone which is reached in a case that the molten resin is brought in contact and kneaded with the physical foaming agent; communicating the high pressure kneading zone and the pressure reduction zone; lowering a pressure of the molten resin brought in contact and kneaded with the physical foaming agent so as to separate the gasified physical foaming agent from the molten resin; controlling a back pressure of the screw to be a second pressure which is not less than the first pressure, and measuring a predetermined amount of the molten resin from which the gasified physical foaming agent has been separated; and foaming and molding the measured molten resin into a desired shape. using a molding apparatus including a plasticizing cylinder having a high pressure kneading zone in which a molten resin, obtained by plasticizing a thermoplastic resin, is brought in contact and kneaded with a physical foaming agent, and a pressure reduction zone in which the gasified physical foaming agent is discharged from the molten resin brought in contact and kneaded with the physical foaming agent; and a screw arranged rotatably and movably back and forth in the plasticizing cylinder; plasticizing the thermoplastic resin to provide the molten resin; shutting off communication between the high pressure kneading zone and the pressure reduction zone; bringing in contact and kneading the molten resin with the physical foaming agent in a state that the communication between the high pressure kneading zone and the pressure reduction zone is shut off; controlling a pressure of the pressure reduction zone to be a first pressure in a state that the communication between the high pressure kneading zone and the pressure reduction zone is shut off, the first pressure being not less than an atmospheric pressure and not more than a maximum pressure of the high pressure kneading zone which is reached in a case that the molten resin is brought in contact and kneaded with the physical foaming agent; communicating the high pressure kneading zone and the pressure reduction zone; lowering a pressure of the molten resin brought in contact and kneaded with the physical foaming agent so as to separate the gasified physical foaming agent from the molten resin; controlling a back pressure of the screw to be a second pressure which is not less than the first pressure, and measuring a predetermined amount of the molten resin from which the gasified physical foaming agent has been separated; and foaming and molding the measured molten resin into a desired shape.