A head-mounted display, a smart phone, a tablet terminal, an electronic book, or the like monitors conditions of the side of a power generation apparatus that charges a battery. An image display apparatus includes a power generation information acquisition means for obtaining power generation information on a power storage amount, a power generation amount, and the like of a secondary battery in each power generation apparatus, appropriately processes the obtained information, and displays it to a user via a display unit. The user can check the power generation amount of the power generation apparatus and the power storage amount of the secondary battery without stopping the use of the image display apparatus. When a power storage amount of a battery in use is lowered, the user can properly judge with which of the power generation apparatuses the user should replace the battery.
