An optical scanning system of a bar code reader utilizing a hologram scanner in which a laser beam from a laser beam generator is divided into three parallel paths by three beam splitters. The beams pass through three focusing lenses and first reflectors. Each of the beams are focused into three holes in second reflectors before being directed in a perpendicular to a hologram disk. The hologram disk deflects the laser beams outwardly before being reflected again by third reflectors. These beams from the third reflectors are used for scanning an article having a bar code with star-shaped pattern beam through a window formed in a housing. The beams are reflected and contain bar code information. The reflected beams are passed back through the window and are reflected by the third reflectors respectively before passing through a hologram disk and being focused and reflected again at the second reflectors. The beams then pass through three pin holes, so that they are detected by photo-detectors.