A temperature-measuring apparatus includes a heat source capable of changing a heat generation temperature, a temperature sensor that detects a temperature of a predetermined position other than a measurement target accommodated in a measurement subject, and a temperature computation portion that computes a temperature of the measurement target on the basis of heat balance characteristics of the temperature of the measurement target, a temperature of the heat source, and the temperature of the predetermined position, the temperature of the heat source, and the detected temperature of the predetermined position.