Disclosed is an optical element that includes: carrier generation layer (16) in which carriers are generated by light from light guide body (12) into which light from a light-emitting element enters; plasmon excitation layer (17) that has a plasma frequency higher than the frequency of light generated when carrier generation layer (16) is excited by light from the light-emitting element; and wave vector conversion layer (18) that converts surface plasmon generated by plasmon excitation layer (17) light having a predetermined exit angle to output the light. Plasmon excitation layer (17) is sandwiched between two layers having dielectric properties. The effective dielectric constant of the incident side portion of plasmon excitation layer (17) including an entire structure stacked above light guide body (12) side is higher than that of the exit side portion of plasmon excitation layer (17) including the entire structure stacked above wave vector conversion layer (18) side and the medium in contact with wave vector conversion layer (18).