To correctly align a door locking link protruded into a cabin from a through hole provided in a door inner panel, and an insert-through hole of a trim cover for covering the outer surface of the panel, and perform work of inserting the link through the insert-through hole easily and positively so as to heighten the workability of fitting the trim cover to the panel.

A through hole 21 provided in a door inner panel 2 so as to insert a door locking link 6 with play is provided with a holding means 7 formed of a protruding piece and a recessed part 71 for temporarily holding the link 6. In the state of temporarily holding the link 6 by the holding means 7, the link 6 and an insert-through hole 51 of a trim cover 5 are aligned to fit the trim cover 5 to the panel 2.