Provided is an apparatus for estimating a target component, the apparatus including a temperature controller configured to modulate temperature of an object, a measurer configured to measure a spectrum for each temperature of the object that changes based on the modulation, and a processor configured to obtain effective optical pathlength vectors corresponding to a temperature change based on the spectrum for each temperature of the object, obtain a representative effective optical pathlength based on the obtained effective optical pathlength vectors, and obtain a target component estimation model based on the obtained representative effective optical pathlength.