1. An image display apparatus that displays a biological state image showing the state of autonomic nerves based on detected biological information, the apparatus comprising: a display section that displays an image; an information acquisition section that acquires predominance level of sympathetic nerve and parasympathetic nerve and an activity magnitude of the autonomic nerve based on the biological information; an image generation section that generates the biological state image in which a figure having a size according to the acquired activity magnitude of the autonomic nerves is set along a first axis, along one side of which the predominance level of the sympathetic nerve is set with respect to a reference point and along the other side of which the predominance level of the parasympathetic nerve is set with respect to the reference point, in a position according to the acquired predominance levels of the sympathetic nerve and the parasympathetic nerve, wherein in the biological state image generated by the image generation section, the figure is set along the first axis whenever the predominance level of the sympathetic nerve and the parasympathetic nerve and the activity magnitude of the autonomic nerve are acquired, and a portion where the figure overlaps with another figure has a color deeper than the color of a portion where the figures do not overlap with each other; and a display control section that causes the display section to display the generated biological state image.