The present invention provides a compact liquid crystal panel detection device which can determine a defect address rapidly and accurately. The detection device comprises a first polarizing film and a second polarizing film which are arranged at the upper and lower parts of a liquid crystal panel on a workbench respectively; a backlight unit which irradiates the liquid crystal panel at a right angle with the lower surface, from the lower surface of the liquid crystal panel on the workbench, and via the second polarizing film; an inclined illumination light source which irradiates the liquid crystal panel on the workbench aslant from the lower part of the lower surface; a probe unit for applying voltages on the pixels of the liquid crystal panel on the workbench to detect the bright spots of the liquid crystal panel; a camera head for shooting the upper surface of the liquid crystal panel under the state of selectively receiving any one of the irradiation light coming from the backlight unit and the inclined irradiation light coming from the inclined illumination light source, and via the first polarizing film; and a reflecting part for guiding the inclined illumination light to the lower surface of the liquid crystal panel in a manner that the inclined illumination light is irradiated to the liquid crystal panel at an appropriate incident angle.