An AC adapter having a dual-bodied plug that can be rotated by 90 degrees relative to the adapter case so that the plug can be stored in the case when the adapter is not used and drawn out of the case when the adapter is in use. A blade distance adjusting unit provided in the case adjusts the distance between the blades of the plug. When the plug is drawn out of the case, the distance between the blades is increased up to the predetermined value. When the plug is stored in the case, the distance between the blades is reduced. The AC adapter can use a thinner case than conventional AC adapters of which plugs are monolithically structured.