A gear machining apparatus includes a rough working tool having a plurality of replaceable tool blades attached to a tool main body, such that the tool blades are arranged in a circumferential direction of the tool main body and blade tips of the tool blades are oriented outward in a radial direction of the tool main body, a finish working tool having a plurality of tool blades provided to a tool main body in a similar manner to the rough working tool, and machining controllers control to perform rough and finish machinings on the workpiece, such that the working tools are rotated on center lines in axial directions of the working tools, the workpiece is rotated on a center line in axial direction of the workpiece, and the working tools are relatively moved to the workpiece along the center line in the axial direction of the workpiece.

A gear machining apparatus includes a rough working tool having a plurality of replaceable tool blades attached to a tool main body, such that the tool blades are arranged in a circumferential direction of the tool main body and blade tips of the tool blades are oriented outward in a radial direction of the tool main body, a finish working tool having a plurality of tool blades provided to a tool main body in a similar manner to the rough working tool, and machining controllers control to perform rough and finish machinings on the workpiece, such that the working tools are rotated on center lines in axial directions of the working tools, the workpiece is rotated on a center line in axial direction of the workpiece, and the working tools are relatively moved to the workpiece along the center line in the axial direction of the workpiece.

To provide a gear machining device and a gear machining method which achieve machining of tooth flanks having different torsion angles with high degree of accuracy. In a gear machining device, a side surface of a tooth of a gear includes a first tooth flank and a second tooth flank having a different torsion angle from the first tooth flank, a cutting blade of a machining tool has a blade traces having a torsion angle determined based on a torsion angle of the second tooth flank and an intersection angle between a rotation axis of a workpiece and a rotation axis of the machining tool so as to allow the second tooth flank to be machined on the pre-machined first tooth flank.