The sight line of an avatar can be set to a direction independent of a direction in which the avatar moves in a virtual reality space. Buttons 219 and 220 are provided for setting the sight line of the avatar to the direction independent of the direction in which the avatar moves in the virtual reality space. According to the operations of these buttons, the processing for changing sight line directions is performed. For example, the novel constitution allows the avatar to walk on the ground while looking up, thereby preventing unnatural display or unnatural avatar movement in which, when the avatar walks looking up, the avatar moves in the direction of its sight line to be eventually raised away from the ground.