An optical component including a multi-layer substrate, an optical waveguide element, and two optical-electro assemblies is provided. The multi-layer substrate includes a dielectric layer, two circuit layers, and two through holes passing through the dielectric layer. The optical waveguide element is located on the multi-layer substrate and between the through holes. The optical-electro assemblies are respectively inserted into the corresponding through holes and correspondingly located at two opposite ends of the optical waveguide element. One of the optical-electro assemblies transforms an electrical signal into a light beam and provides the light beam to the optical waveguide element, and the other one of the optical-electro assemblies receives the light beam transmitted from the optical waveguide element and transforms the light beam into another electrical signal. A manufacturing method of the optical component and an optical-electro circuit board having the optical component are also provided.