An exemplary portable electronic device includes a main body defining a shaft receiving hole an inner surface in the shaft receiving hole, a camera unit mounted on the main body, and a fastening member. The camera unit includes a camera module, and a shaft connected with the camera module. The shaft is rotatably received in the hole, and axially movable relative to the main body. The inner surface and the shaft cooperatively define a wedge-shaped space. The fastening member includes an elastic portion. The elastic portion is slidable between a first position where the elastic portion is engaged in a narrow end of the space, and the shaft is securely fastened to the main body by the elastic portion, and a second position where the elastic portion is disengaged from the narrower end of the space, and the shaft is unfastened from the main body.