1. A reaction-curable-resin cured-state measuring apparatus comprising: an ultraviolet light source for irradiating ultraviolet light to a reaction curable resin serving as an object to be measured; detection means for detecting reflected ultraviolet light or transmitted ultraviolet light from the reaction curable resin as screen image data having a certain area; and image processing means for arithmetic-processing the screen image data detected by the detection means and quantifying the progress state of a curing reaction of the reaction curable resin following the passage of time as screen image.