A display apparatus comprising: (i) a glasses-type frame that is mounted on the head of an observer; (ii) an image display device that is attached to the frame, wherein the image display device includes an image forming device (151, 153), and an optical device on which light emitted from the image forming device (151, 153) is incident, in which the light is guided, and from which the light is emitted; and (iii) a light control device that adjusts an amount of external light incident from the outside is provided in a region of the optical device from which light is emitted, and wherein the light control device includes two opposite transparent substrates (701, 703) comprising a first substrate and a second substrate, transparent electrodes (702, 704) comprising a first transparent electrode and a second transparent electrode that are provided on the first substrate and the second substrate, respectively, and an electrophoretic dispersion liquid that is sealed between the two substrates (701, 703), wherein the optical device includes: (a) a light guide plate in which incident light propagates while being totally reflected and from which the light is emitted; (b) a first deflection unit that deflects light incident on the light guide plate so as to be totally reflected in the light guide plate; and (c) a second deflection unit that deflects the light, which propagates in the light guide plate while being totally reflected, a plurality of times so as to be emitted from the light guide plate, wherein the light and the optical device are sealed by a sealing member, and there is a gap between the first transparent substrate and the light guide plate, and the first transparent electrode is patterned and the second transparent electrode is not patterned. (i) a glasses-type frame that is mounted on the head of an observer; (ii) an image display device that is attached to the frame, wherein the image display device includes an image forming device (151, 153), and an optical device on which light emitted from the image forming device (151, 153) is incident, in which the light is guided, and from which the light is emitted; and an image forming device (151, 153), and an optical device on which light emitted from the image forming device (151, 153) is incident, in which the light is guided, and from which the light is emitted; and (iii) a light control device that adjusts an amount of external light incident from the outside is provided in a region of the optical device from which light is emitted, and wherein the light control device includes two opposite transparent substrates (701, 703) comprising a first substrate and a second substrate, transparent electrodes (702, 704) comprising a first transparent electrode and a second transparent electrode that are provided on the first substrate and the second substrate, respectively, and an electrophoretic dispersion liquid that is sealed between the two substrates (701, 703), wherein the optical device includes: (a) a light guide plate in which incident light propagates while being totally reflected and from which the light is emitted; (b) a first deflection unit that deflects light incident on the light guide plate so as to be totally reflected in the light guide plate; and (c) a second deflection unit that deflects the light, which propagates in the light guide plate while being totally reflected, a plurality of times so as to be emitted from the light guide plate, wherein the light and the optical device are sealed by a sealing member, and there is a gap between the first transparent substrate and the light guide plate, and the first transparent electrode is patterned and the second transparent electrode is not patterned. two opposite transparent substrates (701, 703) comprising a first substrate and a second substrate, transparent electrodes (702, 704) comprising a first transparent electrode and a second transparent electrode that are provided on the first substrate and the second substrate, respectively, and an electrophoretic dispersion liquid that is sealed between the two substrates (701, 703), (a) a light guide plate in which incident light propagates while being totally reflected and from which the light is emitted; (b) a first deflection unit that deflects light incident on the light guide plate so as to be totally reflected in the light guide plate; and (c) a second deflection unit that deflects the light, which propagates in the light guide plate while being totally reflected, a plurality of times so as to be emitted from the light guide plate,