Abstract: An optical measuring apparatus used for measuring optical characteristics of a liquid crystal display panel (LCD panel) in a calibration thereof comprises a housing having a contacting portion directly contacting a surface of the LCD panel and disposed far from a region on the LCD panel to be measured. An optical system and a photosensor is provided in the housing with a predetermined positional relation, so that ambient illumination is shielded by the housing and stray rays emitted from the LCD panel and having exit angles larger than a predetermined maximum exit angle &agr; are restricted by the optical system.