An optical inspector includes a radiating source, a time varying beam reflector, a telecentric scan lens, a first and second waveplate, a polarizing beam splitter, a first detector, a focusing lens, a blocker, and a second detector. A lead which is branched from one image signal line and crosses the other image signal lines is a parallel connection of a first layer lead and a second layer lead. The coupling element has spring arms resiliently insertable into a bore defined in a central pin of the coaxial connector.