An optical fiber temperature distribution measuring device includes: an optical fiber as a sensor; a light source for outputting, to the optical fiber, signal light which has been amplified by excitation light; a temperature distribution calculation unit for measuring a temperature distribution along the optical fiber by using backward Raman scattered light from the optical fiber; an ASE light intensity variation measurement unit for measuring an intensity variation of an ASE light generated at the light source; and a temperature distribution correction unit for correcting the temperature distribution based on a measurement result of the ASE light intensity variation measurement unit.