PURPOSE: To manufacture a composite injection molded material of optical shape by using two units of injection molding machines and molding a primary molded material and a secondary molded material on separate injection molding machines.

CONSTITUTION: A transfer device C for releasing and transferring a primary molded material injection molded in an injection molding machine A to an injection molding machine B is arranged between the first injection molding machine A and the second injection molding machine B. Movable cylinders 61 and 62 moving on traversing rails 65 and 66 are mounted on fixed platens 2 and 12 of the transfer device C, and suction sections 63 and 64 for sucking the molded material are provided at the ends of the same, and a chuck 67 rotatable by a motor 68 for rotation is installed movably on a rail 69. When a primary molded material 40 molded by the injection molding machine A is in the plastic deformable state, a second kind resin is injected by opening a mold D and the material is released by means of the transfer device C, and then the same is inserted into a mold E of the injection molding machine B, and the mold E is opened after the filled resin is solidified and a composite injection molded material is released.