Apart installation structure for a vehicle for attaching a part to a vehicle body through a bracket using an access hole established in the vehicle body and a surrounding portion of the access hole, comprises a bolt including a head capable of passing through the access hole and a thread section projecting from the head and passing through the access hole, a plate member including an opening section and capable of being attached to the thread section through the opening section, a nut for being screwed onto the thread section and for tightening the surrounding portion, the plate member and the bracket altogether, and a rotation stopper provided on the bracket for contacting the head after passing through the opening section and the access hole so as to restrict a rotation when the nut is screwed in.