A portable electronic device includes a base, a cove, a first plate, a second plate, a first post, a second post, and an adjusting mechanism. The first plate is secured to the cover. A guiding slot and a receiving hole are defined in the first plate. The second plate is secured to the base. A receiving slot and a pin hole are defined in the second plate. The first post passes through the pin hole and the receiving hole. The second post passes through the receiving slot and is slidably received in the guiding slot. One end of the adjusting mechanism is rotatably connected to the first and second plates by the first post, and the other end of the adjusting mechanism is slidably connected to the first and second plates by the second post.