An image display optical system which achieves a small size and display at a wide angle of view as well as maintains a required level of optical performance and allows suppression of occurrence of various aberrations at the same time. The optical system includes a first optical element and a second optical element in order from the side of an exit pupil of the optical system to the side of a display device. A combined negative optical power is provided by an emergent surface of the second optical element and an incident surface of the first optical element, and the optical system forms an intermediate image with the displaying luminous flux in the first optical element.