Abstract: A virtual image display device includes a projection optical system that includes a projection mirror that projects an image display light toward a concavely curved surface of a virtual image presentation plate. The projection mirror has a convexly curved surface on which the image display light is incident and reflected diagonally and is arranged such that a direction orthogonal to both a direction of incidence and a direction of reflection of the image display light on the concavely curved surface and a direction orthogonal to both a direction of incidence and a direction of reflection of the image display light on the convexly curved surface are parallel to each other. The display unit is provided at a focal point of a composite optical system within a meridional plane, the composite optical system being formed by the virtual image presentation plate and the projection optical system.