A numerical control device includes: an estimation unit to estimate an accumulation amount of swarf to be produced when a tool mounted on a machine tool cuts a workpiece on the basis of a machining condition in cutting the workpiece by the tool and a value of current to be applied to a motor for moving a shaft of the machine tool when the tool cuts the workpiece. The numerical control device further includes a correction unit to correct the accumulation amount of swarf estimated by the estimation unit on the basis of a machining mode specifying a shape of swarf to be produced when the tool cuts the workpiece.