A portable electronic device comprises a housing, a circuit board, a heat-conduction structure and a heat-dissipation structure. The circuit board is disposed in the housing. The heat-conduction structure is disposed in the housing and contacts the circuit board. The heat-dissipation structure is disposed outside the housing and connected to the heat-conduction structure, wherein heat is transmitted from the circuit board, passing the heat-conduction structure and the heat-dissipation structure to be dissipated out of the housing.