A portable electronic apparatus including a case, a speaker, a sound box cover, a first circuit board and a second circuit board is provided. The case has a sound hole and a plurality of limiting portions disposed around the sound hole. The speaker corresponding to the sound hole is disposed in the case. The sound box cover covers the speaker to define a back sound chamber among the sound box cover, the case and the speaker. The first circuit board is disposed in the case. The second circuit board with a first surface, a second surface and a plurality of pads is disposed on the sound box cover. The second circuit board is exposed on the sound box cover with the first surface. The second circuit board electrically connects to the first circuit board and the speaker through the pads respectively disposed on the first and the second surface.