A hinge structure is disclosed to include a first hinge structure and a second hinge structure respectively mounted on the base member and cover of a lifter cover type mobile electronic product, two master connecting members coupled between the first hinge structure and the second hinge structure for allowing the cover to be opened from the base member, and two auxiliary connecting members coupled between the first hinge structure and the second hinge structure in such a manner that the auxiliary connecting members lock the cover to the second hinge structure and the cover is closed on the base member, and unlock the cover from the second hinge structure for adjustment of the inclined angle of the cover when the cover is opened from base member.