A locking part structure for a vehicle, which includes a door, locking means for locking the door to a vehicle body when the door is closed, and an auxiliary plate that connects the door to the locking means. The locking means comprises a door side locking part that is set in a lock opening formed in the door, and a vehicle body side locking part that is disposed on a vehicle body side and engages with the door side locking part when the door is closed. The auxiliary plate comprises a door fixing part to be fixed to the door, a lock fixing part to be fixed to the door side locking part, and a bending part that is disposed between the door fixing part and the lock fixing part, and formed in a bending form so as to be stretchable.