The present invention provides a transmission guided-mode resonant grating integrated spectroscopy device (transmission GMRG integrated spectroscopy device) characterized by comprising, disposed in this order on an optical detector array in which a plurality of diodes are mounted on a substrate made of a semiconductor: a transparent spacer layer; a waveguide layer; a transparent buffer layer provided as desired; a transmission metallic grating layer having a thickness causing surface plasmon; and a transparent protection film layer which is provided as desired.