An electronic device including a first casing, a second casing, at least one first connecting unit and at least one feeding unit is provided. The first casing includes a conductive material. The second casing includes a conductive material. The first casing and the second casing are conducted with each other through the first connecting unit. The feeding unit is electrically connected to the first casing and the second casing, wherein the electronic device forms an antenna structure with the first casing, the second casing, the first connecting unit and the feeding unit and transmits an electromagnetic signal via the feeding unit.