A portable electronic device includes a main body, a battery module, at least a cover, a latch, a resilient member and a knob. The battery module is connected to the main body. At least a cover is connected to the main body. The latch is to lock or unlock the battery module and the at least a cover to the main body. The resilient member has an end connected with the latch for recovering the latch to an original position. The knob is connected to the latch and exposed by the main body for controlling the latch to lock or unlock the battery module and the at least a cover.