PURPOSE: To provide effectiveness in the fields of compensation of manufacturing error, absorption of vibration, and noise elimination by cutting out the center part of the rim or boss of a gear to the gear tooth bottom circle with leaving the supporting parts in its both ends to provide each gear tooth with a double end supporting structure.

CONSTITUTION: The center part of the rim or boss of a gear is cut out to the gear tooth bottom circle 1 with leaving the supporting parts 2 in its both ends to provide each gear tooth with a double-end supporting structure. Hence, the minute displacement of the tooth part is made easy, whereby the effectiveness is exhibited in the fields of compensation of manufacturing error, absorption of vibration, and noise elimination.