A foldable electronic device with an antenna including a first body, a second body, a pivotal mechanism, an antenna and a driving element is provided. The first body has a holding recess on one side thereof. The second body is located on the other side of the first body. The pivotal mechanism is used to pivotally connect the first body to the second body. Two sides of the driving element are connected to the pivotal mechanism and the antenna, respectively. When the first body is opened relatively to the second body, the pivotal mechanism drives the driving element to generate a first linear displacement. The first linear displacement drives the antenna to have a second rotation displacement to allow the antenna to extend out of the receiving groove.