The present invention relates to a portable information processing device having a body part (2) and a display part (3) supported so that it can open/close and rotate on the body part (2). The portable information processing device has a stereo microphone (53) provided in the display part (3), a detecting unit (83) for detecting the opening/closing state and the rotating state of the display part (3) with respect to the body part (2), a control unit for allocating a first channel signal and a second channel signal of an audio signal outputted from the stereo microphone (53) to a right channel signal and a left channel signal on the basis of the result of the detection by the detecting unit, and a recording unit for recording the audio signal allocated by the control unit. The inputted audio signal is appropriately allocated to a right channel signal and a left channel signal and thus recorded in accordance with the opening/closing state and the rotating state of the display part (3) with respect to the body part (2) and the rotating state of an image pickup unit with respect to the display part (2).