In a door hinge device for vehicles, in a vehicle without a B pillar, a hinge slider connected to a hinge portion of a door slidably moves in an external diagonal direction of a vehicle body along a rail in a case to secure a rotational trajectory of the door, and then a first striker configured in the hinge slider is restrained to a hinge latch unit fixed onto the rail inside the case in association with an action of a second striker provided at one side of the door to fix a slide movement location of the hinge slider, stably achieving an opening/closing operation of the door.