PROBLEM TO BE SOLVED: To provide a method for producing a metal powder sintered compact in which cracks and blister generated in a production process are prevented, and further, the removal of a core after injection molding is facilitated.SOLUTION: Regarding a method in which a metal powder compound is injection-molded using a cavity formed by a mold 13 and a core 12, the core 12 is removed from the obtained molded body 14, and the molded body 14 is degreased and sintered to produce a metal powder sintered compact having a hollow part or an undercut part, the core 12 is composed from a water-soluble resin, or composed from a water-soluble resin added with a water-soluble filler or a water-insoluble filler at a prescribed ratio or composed of a water-insoluble resin added with a water-soluble filler at a prescribed ratio, and the removal of the core is performed by eluting a part or the whole of the core 12 at the inside of the molded body 14 using water.
