A method for processing a gear includes a first cutting process starting the cutting of a work by moving a cutter in a first cutting direction while maintaining a cutting depth of the work at a setting value and reducing the cutting depth of the work before a first cutter portion reaches an end portion of a cutting area in the first cutting direction and a second cutting process synchronously rotating the work and the cutter in a reverse direction of rotational directions of the work and the cutter in the first cutting process, maintaining the cutting depth of the work at the setting value, and cutting the end portion of the cutting area by moving the cutter in a second cutting direction.