Optical element and optical device including the same

An optical element comprising:

• a substrate made of a resin material;
• and
• an antireflection film,
• wherein the antireflection film consists of a dielectric layer formed on the substrate and a porous layer formed on the dielectric layer,
• the dielectric layer includes a first layer, and a second layer adjacent to the first layer and the porous layer,
• the porous layer comprises silicon oxide or magnesium fluoride,
• the first layer comprises silicon oxide at a weight ratio of 90% or more and aluminum oxide at a weight ratio of 10% or less,
• the second layer comprises tantalum oxide, and
• wherein the following inequality is satisfied:
• 1.15≤n≤1.35
• where n is a refractive index of the porous layer for the d-line.