Antireflection film and optical member

An antireflection film that is provided on a surface of a substrate, the film comprising:

• an uneven structure layer that has an uneven structure in which a distance between protrusions is shorter than a wavelength of light of which reflection is to be suppressed, and that has an alumina hydrate as a main component;
• and
• an intermediate layer that is disposed between the uneven structure layer and the substrate, wherein:
• the uneven structure layer has a spatial frequency peak value of the uneven structure of 6.5 μm−1 or greater and has a film thickness of 250 nm or more,
• the uneven structure layer exhibits a profile in which a refractive index of the uneven structure layer in a film thickness direction gradually increases from a surface side, a maximum peak is exhibited in a region from a center of the uneven structure layer in the film thickness direction to an interface with the intermediate layer, and the refractive index gradually decreases toward the interface to a refractive index that is at least 10% smaller than the maximum peak,
• the intermediate layer comprises a plurality of layers including at least a first layer, a second layer, a third layer, a fourth layer, a fifth layer, a sixth layer, a seventh layer, and an eighth layer in this order from the uneven structure layer side to the substrate side,
• the first layer has a refractive index of 1.42 or more and less than 1.7 and a film thickness of 2 nm or more and 20 nm or less,
• the second layer has a refractive index of 1.7 or more and 2.7 or less and a film thickness of 2 nm or more and 30 nm or less,
• the third layer has a refractive index of 1.42 or more and less than 1.7 and a film thickness of 10 nm or more and 200 nm or less,
• the fourth layer has a refractive index of 1.7 or more and 2.7 or less and a film thickness of 2 nm or more and 30 nm or less,
• the fifth layer has a refractive index of 1.42 or more and less than 1.7 and a film thickness of 10 nm or more and 200 nm or less,
• the sixth layer has a refractive index of 1.7 or more and 2.7 or less and a film thickness of 2 nm or more and 30 nm or less,
• the seventh layer has a refractive index of 1.42 or more and less than 1.7 and a film thickness of 10 nm or more and 200 nm or less, and
• the eighth layer has a refractive index of 1.7 or more and 2.7 or less and a film thickness of 2 nm or more and 30 nm or less.