An optical inspection apparatus includes a dichroic mirror, a first light source, and a first image capturing device. The dichroic mirror has a first side and a second side opposite to the first side. The dichroic mirror transmits a first light beam and reflects a second light beam. The wavelength of the second light beam is different from the wavelength of the first light beam. The first light source is disposed at the first side of the dichroic mirror and is configured to provide the first light beam to pass through the dichroic mirror. The first image capturing device is disposed at the second side of the dichroic mirror and is configured to detect the second light beam reflected from the dichroic mirror.