A numerical control device for a working machine capable of controlling a tool posture relative to a workpiece using rotational driving of a rotary drive axis about a machine control point includes: an interpolation unit that performs an interpolation process on moving data generated from a machining program and outputs a position of the machine control point for each interpolation point; a coordinate transformation unit that transforms a position of the machine control point to a tool tip-point position; a stroke-limit determination unit that determines whether the position of the machine control point and the tool tip-point position fall within a range of a movable region, and selects and outputs a stroke limit signal indicating a stroke limit and a tool-posture changing command for instructing change of the tool posture; and a tool-posture changing unit that changes the tool posture in response to the tool-posture changing command.