An optical distance sensor comprising a first substrate provided with a light-emitting element and a light-receiving element, an optical structure formed integrally on a second substrate and having a plurality of optical elements for focusing the light emitted from the light-emitting element and the light reflected from an object to be measured in a direction parallel to the plane of the second substrate, and a lens for focusing the light emitted from the light-emitting element and the light reflected from the object in a direction perpendicular to the plane of the second substrate. Thus a small optical distance sensor can be produced inexpensively without requiring an expensive three-layer waveguide and an optical fiber difficult to handle.