An image display apparatus (20a, 20b), comprising: a light source; an image generator that modulates light emitted from the light source and generates image light; and a projection optical system including a lens system that is configured on a basis of a reference axis at a position on which the generated image light is incident, and that has a positive refracting power as a whole, and a concave reflective surface that is configured on a basis of the reference axis, and that reflects the image light emitted from the lens system toward a projection target, wherein the concave reflective surface reflects at least one or more light beams (C1, C2, C3, C4) included in the image light incident on the concave reflective surface, toward a direction that intersects with a direction along the reference axis at an angle of 80 degrees or more, the concave reflective surface is configured to have an axis of rotational symmetry that coincides with the reference axis, and the image display apparatus is configured to satisfy a relationship: 1 < Z ′ 1.0 ⋅ hmax − Z ′ 0.9 ⋅ hmax / Z ′ ave. < 20, where h represents a height of the light beam above the reference axis, Z'(h) represents a derivative function obtained by differentiating a function Z(h) with respect to the height of the light beam, the function Z(h) represents a shape of the concave reflective surface corresponding to the height of the light beam, hmax represents a height of a light beam corresponding to a reflection point situated farthest from the reference axis for reflecting the image light, and Z'ave. represents an average value of the Z'(h) from the reference axis to the height hmax of the light beam. a light source; an image generator that modulates light emitted from the light source and generates image light; and a projection optical system including a lens system that is configured on a basis of a reference axis at a position on which the generated image light is incident, and that has a positive refracting power as a whole, and a concave reflective surface that is configured on a basis of the reference axis, and that reflects the image light emitted from the lens system toward a projection target, wherein a lens system that is configured on a basis of a reference axis at a position on which the generated image light is incident, and that has a positive refracting power as a whole, and a concave reflective surface that is configured on a basis of the reference axis, and that reflects the image light emitted from the lens system toward a projection target, wherein the concave reflective surface reflects at least one or more light beams (C1, C2, C3, C4) included in the image light incident on the concave reflective surface, toward a direction that intersects with a direction along the reference axis at an angle of 80 degrees or more, the concave reflective surface is configured to have an axis of rotational symmetry that coincides with the reference axis, and the image display apparatus is configured to satisfy a relationship: 1 < Z ′ 1.0 ⋅ hmax − Z ′ 0.9 ⋅ hmax / Z ′ ave. < 20, where h represents a height of the light beam above the reference axis, Z'(h) represents a derivative function obtained by differentiating a function Z(h) with respect to the height of the light beam, the function Z(h) represents a shape of the concave reflective surface corresponding to the height of the light beam, hmax represents a height of a light beam corresponding to a reflection point situated farthest from the reference axis for reflecting the image light, and Z'ave. represents an average value of the Z'(h) from the reference axis to the height hmax of the light beam.