Vehicle seat reclining device and production method therefor

A vehicle-seat reclining device includes a seat cushion frame, a seat back frame, a first base plate, a second base plate, and an internal gear recessed in one surface of the second base plate. A fitting projection having an outline that is concentric and in phase with that of the internal gear projects from the other surface of the second base plate, and a fitting hole is provided in the seat back frame so as to be fitted on the fitting projection.