A display apparatus for displaying a virtual image superposed upon a real world image, which can automatically set the focus of a lens to the virtual image, a virtual world image object having a high importance degree or a real world image object having a high importance degree. The display apparatus has a lens for capturing light from a real world, a lens state control unit for controlling a state of the lens including a focus, a storage unit for storing computer image data, a computer image generation unit for generating a computer image by using the computer image data stored in the storage unit in accordance with lens state information of the lens state and the like; and a synthesis display unit for synthesizing an image captured via the lens and the generated computer image and displaying a synthetic image.