A gear machining apparatus includes a skiving mechanism positioning a work to be machined and a pinion type cutter on axes skewing from each other, the skiving mechanism rotating the work at a predetermined position and feeding the cutter while rotating in a direction of a tooth trace of a gear to be formed at the work synchronously to the rotation of the work for producing the gear from the work. The cutter includes a tooth surface which is formed with an involute region having an involute curve in an area including a pitch circle in a tooth depth direction, an addendum region continuously formed from the involute region to an addendum, and a dedendum region continuously formed from the involute region to a dedendum the addendum region and the dedendum region being shaped in a configuration different from the involute region.