An image display device includes: an optical unit that generates image display light based on an image signal; a projection unit that projects the image display light generated by the optical unit; and a combiner that presents a virtual image by reflecting the image display light projected from the projection unit. The projection unit includes: a first wave plate that converts linearly-polarized image display light emitted from an image display element into circularly-polarized image display light; a diffuser plate that diffuses the circularly-polarized image display light emitted from the first wave plate; a second wave plate that converts the circularly-polarized image display light diffused by the diffuser plate into linearly-polarized image display light; and a polarization plate that transmits the linearly-polarized image display light emitted from the second wave plate.