A numerical control device controls a machine tool that includes a turret to which a tool is attached, the turret being configured to move along an X-axis and rotate on an H-axis, and further includes a workpiece rotatable on a C-axis. There is no direct movement of the machine tool along a Y-axis that is orthogonal to the X-axis. The numerical control device includes an analyzer that analyzes a y-axis rapid-traverse command in a Y-axis interpolation mode; a C-axis interpolation processor that interpolates a C-axis rotation angle range in response to the analyzed Y-axis rapid-traverse command; and an X-axis interpolation processor that interpolates an X-axis position based on the interpolated C-axis rotation angle range, where the numerical control device rotates the C-axis movement at a constant velocity during the entire C-axis rotation angle range, and accelerates an X-axis velocity of the turret accordingly, to thereby perform an operation.