A radiation temperature measuring device includes: an infrared sensor that detects a wavelength including an absorption band by atmosphere; an absorption rate calculation unit that calculates an absorption rate by the atmosphere when measuring a surface temperature of an object from output of the infrared sensor; an output storage unit that stores conversion information for converting the output of the infrared sensor into the surface temperature of the object; a surface temperature calculation correction unit that calculates the surface temperature of the object from the output of the infrared sensor, the absorption rate calculated by the absorption rate calculation unit, and the conversion information; and an absorption rate storage unit that stores in advance the absorption rate by the atmosphere when the conversion information is set, in which the calculated surface temperature of the object is corrected with the absorption rate stored in the absorption rate storage unit.