To simply provide a permanent mold suitable to in the case of mass-producing large thin cast products.

This permanent mold is provided with a molten metal flowing-in part 15 containing a gap-state molten metal flowing passage formed in parting surfaces 3a, 4a or a cavity filled up with the molten metal, and a padding part (leakage preventive part) 30 for preventing the leakage of the molten metal poured into this molten metal flowing-in part 15 from the parting surfaces 3a, 4a. This leakage preventive part 30 is formed as stepping state (30B-30F), in which the differences in levels are progressively higher toward the outer peripheral direction from the center part the parting surfaces 3a, 4a along the peripheral edge of the molten metal flowing-in part 15.