To simultaneously estimate the temperature distribution and the thermal flux distribution in the inner surface and the outer surface of a reaction vessel.

This operation management device for the reaction vessel is provided with an input part 101 for inputting a temperature measured by thermocouple embedded in the wall of the reaction vessel, and an arithmetic part 102 for finding the temperature or the thermal flux in the inner surface and the outer surface of the reaction vessel by performing an inverse problem analysis using a non-steady heat conduction equation from the temperature to be input in the input part 101. The arithmetic part 102 finds an assumed value, or the sum of the square of the difference between the temperature Y measured by the respective thermocouple disposed in one-dimensional direction and the temperature T in the positions of the respective thermocouple calculated from the assumed value of the thermal flux in the inner surface and the outer surface of the reaction vessel by the non-steady heat conduction equation becomes minimum, as the thermal flux in the inner surface and the outer surface of the reaction vessel.