A virtual image display device for presenting a virtual image to a user via a virtual image presentation plate (22, 62) having a uniform thickness (t), comprising: a display unit that generates an image display light; and a projection optical system that includes a projection mirror that projects the image display light toward the virtual image presentation plate such that the image display light is incident and reflected on a concavely curved surface of the virtual image presentation plate diagonally, wherein 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, the projection optical system is configured to have astigmatism due to a difference between the focal point of the composite optical system within the meridional plane and a focal point of the composite optical system within the sagittal plane, the focal point of the composite optical system within the meridional plane is a position of convergence of parallel beams assumed to be incident from the user toward the virtual image presentation plate along the meridional plane of the virtual image presentation plate, the focal point of the composite optical system within the sagittal plane is a position of convergence of parallel beams assumed to be incident from the user toward the virtual image presentation plate along the sagittal plane of the virtual image presentation plate, the projection optical system further includes a plane parallel plate provided between the display unit and the convex projection mirror at an angle to a light path of the projection optical system, the display unit, the plane parallel plate and the convex projection mirror are arranged on a light axis extending in a direction, the plane parallel plate includes a rotational axis, and a direction of the rotational axis of the plane parallel plate is configured to be orthogonal to the meridional plane of the projection optical system. a display unit that generates an image display light; and a projection optical system that includes a projection mirror that projects the image display light toward the virtual image presentation plate such that the image display light is incident and reflected on a concavely curved surface of the virtual image presentation plate diagonally, wherein 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, the projection optical system is configured to have astigmatism due to a difference between the focal point of the composite optical system within the meridional plane and a focal point of the composite optical system within the sagittal plane, the focal point of the composite optical system within the meridional plane is a position of convergence of parallel beams assumed to be incident from the user toward the virtual image presentation plate along the meridional plane of the virtual image presentation plate, the focal point of the composite optical system within the sagittal plane is a position of convergence of parallel beams assumed to be incident from the user toward the virtual image presentation plate along the sagittal plane of the virtual image presentation plate, the projection optical system further includes a plane parallel plate provided between the display unit and the convex projection mirror at an angle to a light path of the projection optical system, the display unit, the plane parallel plate and the convex projection mirror are arranged on a light axis extending in a direction, the plane parallel plate includes a rotational axis, and a direction of the rotational axis of the plane parallel plate is configured to be orthogonal to the meridional plane of the projection optical system.