There is provided an external stereo microphone device that makes it possible to change orientations of microphones over a wide range.An external stereo microphone attached to a mobile electronic device includes a pair of symmetrically-positioned microphones 60, a holder unit 40 having a pair of holders 46 symmetrically positioned so as to accommodate the pair of microphones 60 respectively and a joint 48 for joining the pair of holders 46 together, and a case 14 having a substantially-cylindrical portion 20 that rotatably supports the holder unit 40 and a body 18 that accommodates a circuit board 22 of the case 14. The joint 48 is a substantially-plate-shaped region that joins outer circumferential edges of the holders 46 together and that has a circumferential width which is one-half or less of an entire circumference of the holder unit.