A head mounting display of a goggle type has a display, on which a guide image representing a model performance manipulation and an eyesight image of a practitioner are displayed in a superimposed manner. The guide image is adjusted its display size and position to be displayed on the display based on an image of a keyboard portion included in the eyesight image. Further, resolution and number of colors of the eyesight image are adjusted so as to meet those of the guide image or an animation image, resulting in reduction of data to be processed. Further, a side eyesight image of a hand of the practitioner playing an instrument is taken from the side, and it is determined if the practitioner's hand in the side eyesight image coincides with a model hand posture defined by judgment data which represents model manipulation performed in synchronization with progress of a song.