To efficiently produce a round-edged ammonium nitrate molding without void due to evacuation by injecting molten ammonium nitrate into a vessel so as to satisfy a specific relationship between the volume and depth (in flat plate form), solidifying the molten ammonium sulfate in the vessel, and then taking up the molding with a vacuum pad.

This round-edged void-free ammonium nitrate molding is produced by introducing molten ammonium nitrate 1 into a vessel or mold 10 in such a way that the depth d (cm) of the molten ammonium nitrate introduced into the vessel 10 down to the deepest bottom of the vessel 10 and the volume V (cm3) of the molten ammonium nitrate introduced into the vessel 10 satisfies the formula of V>πd3/4 (that is, so as to become a flat plate), then cooling the molten ammonium nitrate to solidify, and taking up the solidified ammonium nitrate with a vacuum pad. The depth of the surface of the molten ammonium nitrate introduced into the vessel down to the deepest bottom of the vessel is normally 5-100mm. The outside of the vessel 10 is cooled with a cooling medium (preferably water) preferably to a temperature of 0-50°C. The surface level 18 of the cooling medium 18 in the vessel 10 is preferably set higher than the surface 19 of the molten ammonium nitrate in the vessel 10.