The image display apparatus or the head-mounted display unit according to the first embodiment or the second embodiment of the disclosure includes the first mirror, first light deflection means, second mirror and second light deflection means, and converts and emits a light beam emitted from the light source into and as parallel light. Accordingly, an image forming apparatus itself formed, from example, from a liquid crystal display apparatus is not required. Besides, there is no necessity to produce, for example, a two-dimensional image once as an intermediate image in the inside of the scanning means. In other words, an image forming optical system is not required. Therefore, reduction in size of the light source or the scanning means and hence reduction in size and weight of the entire image display apparatus can be anticipated. In the image display apparatus or the head-mounted display unit according to the first embodiment or the second embodiment, the parallel light originating from the light beam emitted from the light source and emitted finally from the second light deflection means is introduced into the eyeballs of an observer. Then, the parallel light passes through the pupil, which usually has a diameter of approximately 2 to 6 mm, of each eyeball and forms an image on the retina, through which it is recognized as one pixel. This is because the light emitted from the second light deflection means is parallel light. Then, such operations are repeated by a plural number of times to allow the observer to recognize a two-dimensional image.