A method for manufacturing a foil decorated molding includes steps of: providing an injection molding device, the injection molding device comprising a male mold and a female mold, the male mold having a projecting part, the female mold defining a cavity; transporting the foil into the injection molding device and between the male and female molds; locking the foil to the female mold to form an airproof space together with the cavity of the female; vacuuming the airproof space to suck the foil toward the female mold; clamping the male and female molds to form a molding space; inputting thermal medium into the molding space to press the foil to cling to an inner surface of the cavity of the female mold; injecting molten resin into the molding space; and cooling and opening the injection molding device, the molten resin cooled forming a molding.