A portable electronic device is described that includes a main body 1, an attachable camera module 2 and a connecting mechanism 12. The attachable camera module 2 comprises a sleeve barrel 20, a lens module 22, a focusing mechanism 24, an image sensor module 26, and a signal linker 212 that transfers image signal from the image sensor module 26 to the main body 1. The connecting mechanism 12 connects to the main body 1 and the attachable camera module 2; the connecting mechanism 12 is installed on one side of the main body 1 to support the attachable camera module 2.