1. A pattern detecting apparatus for inspecting a body which has a wiring pattern on a material capable of generating fluorescent light, comprising: a light source which emits light having both an exciting light component for generating said fluorescent light from a surface of said material and an infrared light component which is separable from the exciting light component for producing reflected light from a surface of the said wiring pattern; a first filter which transmits not only said exciting light component but also said infrared light component from the said light source; a first mirror which directs light received from said first filter to the said body and which transmits fluorescent light from the body and reflected light from the body; a second filter which transmits the fluorescent light received via said first mirror and the reflected light received via said first mirror, and which removes all exciting light reflected from the body through the first mirror; an optical system which includes a second mirror, a fluorescent light detector, a reflected-light detector and a lens for focussing the fluorescent light received from said second filter on said fluorescent-light detector via said second mirror and for focussing the reflected light received from said second filter on said reflected-light detector via said second mirror; and a detection circuit including means for contracting, enlarging and masking pattern images detected by the said detectors.