Aside door structure for a vehicle includes a door beam that has hollow sections which are open at two ends in a longitudinal direction, and a hinge reinforcement member including a bent plate body in a crank shape that is joined to one of a front end and a rear end of the door beam. The hinge reinforcement member forms the crank shape by integrally forming a middle portion that closes an opening in the one of the front end and the rear end of the door beam and is joined to a stepped vertical wall of an inner panel of a side door, an outer end portion that is joined to a stepped outer side wall of the inner panel and an outer wall of the door beam, and an inner end portion that is joined to an inner wall of the door beam.