A lifting mechanism is adapted to bear an expansion unit, and the expansion unit contacts or is separated from a heat dissipating module. The lifting mechanism includes an outer casing base and a bearing base. The bearing base is disposed on the outer casing base liftably along a first axis. The expansion unit is disposed on the bearing base. When the bearing base is located at an original position relative to the outer casing base, the expansion unit on the bearing base is separated from the heat dissipating module. When the bearing base is lifted relative to the outer casing base along the first axis to a lifting position, the expansion unit on the bearing base contacts the heat dissipating module. An electronic device having the lifting mechanism is further provided.