To solve a problem caused by engaging a lock bar projecting to a tail gate lifter side with a lock bar attaching bracket in a side pillar side in a conventional locking device.

In a freight vehicle having a hinged double door, a tail gate lifter for storing by standing the rear part of a door after closing the door, is composed of a lock bar attaching bracket 11 forming a vehicular rear gate structure and attached to a back surface of a side column for joining the hinged double door by a hinge so as to project backward; a lock bar 13 orthogonally attached to a tip end of the lock bar attaching bracket, a slide bar 14 retreatably provided on a side edge of a floor plate 5 of the tale gate lifter in a lateral direction; and a lock bracket 16 orthogonally attached to an end portion of the slide bar and having a hole 15b for fitting the lock bar. A gasket 2 provided on a side edge of the door is prevented from interfering in a tip end of the lock bar attaching bracket 11 at the time of opening/closing the door.