The present invention relates to a portable electronic device, which includes a housing having a receiving space therein, a core element received in the receiving space and having a plug at a front end thereof and a track adjacent to a rear end thereof, and a cam pivotally connected to the housing at a position adjacent to a first end thereof. When the first end of the cam is turned (e.g., by the user) in a certain direction, a second end of the cam is moved toward a plug opening of the housing. As a result, a pin at a second end of the cam presses against the track and thereby pushes the core element and extends the plug out of the housing through the plug opening. Due to the simple structure, the portable electronic device can be rapidly produced by an automated assembly process.