To reduce the number of operation on a vehicle production line in the manufacture of fitting elements for opening/closing a vehicle door.

This vehicle door opening knob fitting device for a door is provided with at least an outer door panel 1 formed to accommodate an opening knob 3 from the outside; a manual opening means; a means for opening using a key; a door end face 2; a mounting module provided with a support plate and a mounting element supported by the support plate; and elements 5 for connecting an opening means for the opening knob 3 to a lock. The fitting device is provided with an intermedite fitting plate 4 supported by the support plate of the module between the fitting device and the outer panel 1, and the opening knob 3 from the outside. The intermedite fitting plate 4 and the opening knob 3 from the outside are provided with means 32, 41 for fixing both the intermedite fitting plate 4 and opening knob 3 from the outside, and means for fixing and previously positioning the elements 5 for connecting the opening means to the lock.