To improve plug productivity and reduce its manufacturing cost while preventing a falling off of a protection film, and also preventing a content of a container such as a drum can from being contaminated with fallen chips of the film by minimizing a finishing cut processing after the plug molding is completed, and applying a protection film such as a painting or a chromeplating to a bottom face of a plug bottom wall evenly and solidly.

A container plug for a drum can and the like having a circular bottom wall 2, a peripheral wall 3 fitted with a male screw part 4 and a flange part 5 is manufactured by a die casting method using a fixed die 10 and movable dies 11, 12. In this case, a molten metal 13 is poured into a plug forming cavity 14 formed inside of the fixed die 10 and the movable dies 11, 12 being fitted to each other from a given peripheral position of a plug peripheral wall male screw part forming space 14b.