A component concentration measuring apparatus includes: a dielectric spectroscopy portion that irradiates a measurement subject with electromagnetic waves and measures a complex permittivity, thereby acquiring a dielectric spectroscopy spectrum; a temperature measurement portion that measures a temperature of the measurement subject; a signal processing portion that corrects the dielectric spectroscopy spectrum according to the temperature measured by the temperature measurement portion; and a calculating portion that applies a calibration model generated in advance from a dielectric spectroscopy spectrum of a sample whose component concentration is known, to the dielectric spectroscopy spectrum corrected by the signal processing portion, thereby calculating a component concentration of the measurement subject. A dielectric spectroscopy sensor that transmits and receives electromagnetic waves and a temperature sensor that outputs a signal that changes in accordance with a temperature are fixed to the measurement probe such that a certain distance is interposed between the sensors.