To improve the quality of a product by uniformly executing the filling of molding sand into a cavity over the whole length of the cavity and uniformly discharging non-hardened molding sand in the cavity over the whole length of the cavity.

This manufacturing device for a hollow core is provided with a metallic mold 1 having an opening part 7 at an end and an opening part 8 at the other end to form the cavity 6 communicating with both end opening parts 7, 8, a molding sand supplying means 9 for filling the molding sand to a molding sand supplying tank 10 in the cavity 6 from the one end opening part 7, and a molding sand discharging means 11 for recovering the non- hardened molding sand filled in the cavity 6 to a discharge sand tank 12 by forcibly discharging from the other end side opening part 8.