A first radiance meter that is provided so as to face an object in an atmosphere in which there is dust and measures the radiance of the object and a second radiance meter that is provided so as not to oppose the object and measures the radiance of the dust between the object and the first radiance meter are used to measure the temperature of the object on the basis of the object radiance that has been measured by the first radiance meter and the radiance of the dust between the object and the first radiance meter that has been measured by the second radiance meter.

A two-color thermometer includes: a first sensor that detects a first intensity that is an intensity of first infrared radiation emitted by an object; a second sensor that detects a second intensity that is an intensity of second infrared radiation emitted by the object at a wavelength different from a wavelength of the first infrared radiation; and a temperature calculator that calculates a first coefficient by inputting, into a correction function, a second coefficient calculated from the first intensity detected by the first sensor and the second intensity detected by the second sensor, and calculates a temperature of the object based on the first coefficient calculated and an intensity ratio between the first intensity and the second intensity. The correction function is calculated from a first correction coefficient and a second correction coefficient that are calculated in advance from a measured temperature of each of different materials.