A hinge device for connecting first and second objects includes a base seat and a sliding member slidably connected to the base seat through a coupling member to be turned about a rotating axis between folded and unfolded states. In the folded state, first and second object connecting sections of the base seat and the sliding member are disposed at two opposite sides of a mounting section of the base seat to allow folding of the objects to each other. In the unfolded state, the second object connecting section is placed above the first object connecting section to allow the second object to be unfolded and inclined to the first object.