TOP-HINGED DOOR STRUCTURE

A top-hinged door structure is obtained that can properly assemble a door to a vehicle body in a structure in which a door holding mechanism for maintaining the door in a fully open posture is provided at only one end side in a transverse direction of an opening portion at the vehicle body. At a back door structure (10), a back door (24), that is rotatably supported at a rear roof header (20) via a pair of door hinges (26), (28), rotates around hinge shafts (30) and opens and closes a rear opening portion (14). The back door (24) is held in a fully open posture that opens the rear opening portion (14), by a single damper (40) that is provided only at a right side with respect to the rear opening portion (14). In the back door structure (10), a fit posture of the back door (24) is corrected due to a vertical position of a mounting surface (20R) of the door hinge (28) at the right side being set at an upper side with respect to a mounting surface (20L) of the door hinge (26) at a left side in a state of not supporting the back door (24).