An apparatus, for positioning a flipping cover relative to a base, includes a first member being fixed relative to the flipping cover, and a second member being fixed relative to the base. The first member defines an arched guiding channel around a rotating axis of the flipping cover. The first member forms at least one raised ridge extending into the guiding channel. The second member forms a guiding rod parallel to the rotating axis. The guiding rod is slidably received in the guiding channel. The guiding rod is deformable to get through the at least one raised ridge. A casing utilizing the above apparatus is also disclosed.