An information processing system includes a display, a display sensor that detects a movement or a rotation of the display, a transducer unit as an earphone unit or a headphone unit, a sound processing part that processes an audio signal so as to localize a sound image in a position outside a head of a listener wearing the transducer unit and listening to sound, and an operation controller that computes an output from the display sensor to obtain a moving direction and a moving distance, or a rotation direction and a rotation angle of the display, and controls sound processing performed by the sound processing part in accordance with a result of the computation so that a positional relation between the display and the head of the listener is mapped as a positional relation between an image display surface and the head of the listener in a virtual viewing space.