There is provided a hole machining method, using a tap tool which rotates about an axis of rotation and which includes a threaded part which has a blade for machining a threaded groove in a pilot hole, and a non-engaging part which forms a space between itself and the pilot hole in a cross-sectional view in which the axis of rotation and a center axis of the pilot hole are aligned, the method including the steps of machining a threaded groove by rotating the tap tool and advancing it toward a workpiece side in a first state in which the center axis and the axis of rotation are aligned, rotating the tap tool about the axis of rotation and moving the tap tool in an interior of the pilot hole toward the non-engaging part side in a direction orthogonal to the axis of rotation to transition the tap tool from the first state to a second state in which engagement between the threaded part and the threaded groove is released, and retracting the tap tool from the threaded hole.

There is provided a hole machining method, using a tap tool which rotates about an axis of rotation and which includes a threaded part which has a blade for machining a threaded groove in a pilot hole, and a non-engaging part which forms a space between itself and the pilot hole in a cross-sectional view in which the axis of rotation and a center axis of the pilot hole are aligned, the method including the steps of machining a threaded groove by rotating the tap tool and advancing it toward a workpiece side in a first state in which the center axis and the axis of rotation are aligned, rotating the tap tool about the axis of rotation and moving the tap tool in an interior of the pilot hole toward the non-engaging part side in a direction orthogonal to the axis of rotation to transition the tap tool from the first state to a second state in which engagement between the threaded part and the threaded groove is released, and retracting the tap tool from the threaded hole.