Propagation optical system and virtual image display device

A propagation optical system incorporated in a virtual image display device, to propagate light emitted from an image display element to a light guide member to display a virtual image, the propagation optical system comprising:

• a first optical system;
• an intermediate optical element;
• and
• a second optical system,
• the first optical system, the intermediate optical element, and the second optical system being sequentially arranged in a direction from the image display element toward the light guide member along an optical axis,
• wherein the intermediate optical element has a non-rotationally symmetric curved surface, of which shape is non-rotationally symmetric about the optical axis,
• wherein, a cross-sectional shape, of the non-rotationally symmetric curved surface, in a first plane including the optical axis is non-arc shape,
• wherein the first plane is a plane in which the non-rotationally symmetric surface has a strongest positive power among planes including the optical axis, and
• wherein the propagation optical system is configured to form, between the first optical system and the second optical system, an intermediate image corresponding to an image displayed on the image display element.