An NC device as a numerical control device controls an additive manufacturing apparatus for producing an object by layering, on a workpiece, a material melted by being irradiated with a beam. The NC device includes: a feature quantity extracting unit that extracts, from image data, a feature quantity for determining a welding state that is a state where a molten material is added to the workpiece; and a process map creating unit that creates a process map in which a shape of the object and a layering condition are associated with each other. The layering condition is selected from among a plurality of layering conditions on the basis of a result of determination of the welding state, and includes at least one of beam intensity and a supply amount of a material.