A hinge includes two brackets and a sliding module. Each bracket has a support shaft and a support plate for supporting a flexible display. The sliding module includes a rail seat, two rail keys, two axle keys and two auxiliary extending frames. The rail seat has two arcuate inboard rails, two receiving slots and two arcuate outboard rails. Each rail key has a key body received in the receiving slot, a sliding protrusion slidable along the arcuate inboard rail, and an arcuate key rail opposite to the sliding protrusion. The axle keys are slidable along the arcuate key rails, and are journalled on the support shafts. The auxiliary extending frames are slidable along the arcuate outboard rails and slidably connected with the support plates. With adjustment of the rails, moving paths of the keys are adjusted to meet the requirement of bending of the flexible display.