Provided are target detection substrate for target detecting apparatuses capable of detecting various targets such as pathogens, biological substances and toxic substances without using a costly measuring apparatus; which can detect these targets with a low measurement error, high efficiency, simplicity, speed and sensitivity; and which can make a quantitative detection thereof. The target detection substrate includes at least a target interaction part which can interact with a target on an optical interference substrate, which optical interference substrate includes a substrate and a different refractive index film having a different refractive index from that of the substrate disposed on the substrate, and interferes irradiated light to radiate it as interference light where the total number of peak tops and peak bottoms in a graph of transmittance against wavelength of the interference light is from 1 to 20 in an arbitrary wavelength range of 100 nm.