Abstract: An object is to improve the quality of molded articles and enable stable molding to be performed. A plasticizing apparatus includes a cylinder member having a molding material supply opening at a predetermined position, a molding material being supplied into the cylinder member via the molding material supply opening; and a metering member rotatably disposed within the cylinder member and adapted to plasticize the molding material when the metering member is rotated. A gas-flow-forming medium hole is formed in the cylinder member at a predetermined position. An open-close apparatus (37) is provided so as to open and close the gas-flow-forming medium hole. Since the open-close apparatus (37) is provided, a gas-flow-forming medium outside the cylinder member can be caused to enter the cylinder member.