A virtual image display device comprising: an image projection device for projecting an image light of an image; an optical axis converting element on which the image light emitted from the image projection device is incident, converting the optical axis of the incident light into a predetermined direction, and emitting the converted light; a diverging element on which the image light emitted from the optical axis converting element is incident, the diverging element reflecting and diverging the image light reflected in a range of a predetermined angle; and a light branching element for reflecting the image light emitted from the optical axis converting element, while transmitting the incident light from the surface other than the reflecting surface, wherein the image light from the image projection device is formed into an image on the diverging element, wherein a virtual image of the image formed on the diverging element is generated on an extension line in the opposite direction to the direction of the image light reflected from the light branching element; wherein the optical axis converting element and the diverging element are arranged so that the image light emitted from the projection device passes through the optical axis converting element and is incident on the diverging element, and so that the image light reflected and diverged by the diverging element passes through the optical axis converting element; and wherein the optical axis converting element is a prism, a prism plate, a holographic element or a lens, wherein the angle from a predetermined horizontal axis of a line connecting the centre of the virtual image and an observation point is defined as θe, wherein the angle from the predetermined horizontal axis of the light branching element is defined as θw, wherein the angle from the predetermined horizontal axis of light emitted from the diverging element that after reflection by the light branching element travels to the observation point along the line connecting the centre of the virtual image and the observation point is defined as θp; wherein the relationship of the angles θe, θw, and θp is expressed as θp=2×θw-θe; wherein the optical axis converting element is provided to be rotatable in the direction perpendicular to the direction of the image light emitted from the optical axis converting element, and wherein the position of the observation range of the virtual image is changed by changing the direction of the image light emitted from the diverging element. an image projection device for projecting an image light of an image; an optical axis converting element on which the image light emitted from the image projection device is incident, converting the optical axis of the incident light into a predetermined direction, and emitting the converted light; a diverging element on which the image light emitted from the optical axis converting element is incident, the diverging element reflecting and diverging the image light reflected in a range of a predetermined angle; and a light branching element for reflecting the image light emitted from the optical axis converting element, while transmitting the incident light from the surface other than the reflecting surface, wherein the image light from the image projection device is formed into an image on the diverging element, wherein a virtual image of the image formed on the diverging element is generated on an extension line in the opposite direction to the direction of the image light reflected from the light branching element; wherein the optical axis converting element and the diverging element are arranged so that the image light emitted from the projection device passes through the optical axis converting element and is incident on the diverging element, and so that the image light reflected and diverged by the diverging element passes through the optical axis converting element; and wherein the optical axis converting element is a prism, a prism plate, a holographic element or a lens, wherein the angle from a predetermined horizontal axis of a line connecting the centre of the virtual image and an observation point is defined as θe, wherein the angle from the predetermined horizontal axis of the light branching element is defined as θw, wherein the angle from the predetermined horizontal axis of light emitted from the diverging element that after reflection by the light branching element travels to the observation point along the line connecting the centre of the virtual image and the observation point is defined as θp; wherein the relationship of the angles θe, θw, and θp is expressed as θp=2×θw-θe; wherein the optical axis converting element is provided to be rotatable in the direction perpendicular to the direction of the image light emitted from the optical axis converting element, and wherein the position of the observation range of the virtual image is changed by changing the direction of the image light emitted from the diverging element.