A grain-component sensor comprises a white LED for emitting a white light as a light emission source, a sample holder in which a sample is filled, a spectroscope for receiving a reflected light from the sample and performing a spectroscopic analysis, and as optical filter provided on an optical path between the white LED and the sample holder, the optical filter has an optical characteristic that is a transmittance of substantially 100 percent in a wavelength band from 950 nm to 1100 nm and cuts a light in a visible light region to substantially 0 percent, a light emitted from the white LED transmits through the optical filter and is irradiated to the sample as a detection light in a wavelength band from 950 nm to 1100 nm, and a diffused reflected light from the sample is condensed by a condenser lens and is entered the spectroscope.
