A portable electronic device has a device body, a hinge unit, a driving unit and a support unit. The device body has a first connecting element. The hinge unit disposes at an end of the device body. The driving unit disposes in the device body and has a second connecting element. The support unit rotates relative to the device body for a closed state and a support state. The support unit has a third connecting element and a fourth connecting element. When the support unit in the closed state, the third connecting element connects with the first connecting element; the fourth connecting element connects with the second connecting element. When the driving unit moves to a driving position, the fourth connecting element detaches from the second connecting element, and the support unit rotates to the support state due to rotation of the hinge unit.