Image display device and projection optical system

An image display apparatus, comprising:

• a light source;
• an image generation unit that modulates light emitted from the light source to generate image light;
• and
• a projection optical system that includes
• a first lens system that has a positive refractive power as a whole and refracts the generated image light,
• a first reflective optical system that has a first reflection surface and a second reflection surface, the first reflection surface folding back and reflecting the image light refracted by the first lens system, the second reflection surface folding back and reflecting the image light reflected by the first reflection surface,
• a second lens system that has a positive refractive power as a whole and refracts the image light reflected by the second reflection surface, and
• a second reflective optical system that has a recessed reflection surface reflecting the image light refracted by the second lens system toward an object to be projected, wherein
• the image display apparatus is configured to satisfy the following relationship:
• 5×10−7<α1<3×10−5, α1 representing a linear expansion coefficient of a first optical part on which the first reflection surface is formed.