A gear machining apparatus causes a machining tool and a workpiece to rotate at a high speed in synchronization with each other to machine a highly accurate gear through cutting. The machining tool is manufactured such that each of pitches between tool blades of the machining tool is an integer multiple of a pitch between teeth of the gear, the integer multiple being equal to or larger than double. By using the machining tool for cutting performed by the gear machining apparatus, the number of the tool blades of the machining tool, which are brought into contact with the workpiece at the same time, is reduced. Thus, it is possible to suppress occurrence of self-excited vibrations during cutting by reducing the cutting resistance. Thus, it is possible to enhance the tooth trace accuracy of the gear.