A catalytic reaction apparatus for carrying out an exothermic catalytic reaction includes a first vessel for containing a first raw material for the exothermic catalytic reaction; a second vessel for containing a second raw material for the exothermic catalytic reaction; a reaction vessel for carrying out therein the exothermic catalytic reaction which is connected to the first and second vessels and receives the first and second raw materials for the exothermic catalytic reaction, the reaction vessel having first and second regions respectively containing first and second catalysts having respective activities different from each other so that the first and second regions have different catalytic performances from one another; a first heat exchanger associated with the reaction vessel and containing a heating medium flowing through the first heat exchanger so that the heating medium receives heat generated by the exothermic reaction in the reaction vessel; a third vessel connected to the first heat exchanger for containing said heating medium and sending the heating medium to the first heat exchangers; a second heat exchanger connected to the first heat exchanger for receiving the heating medium and transferring heat to a heat receptor arranged in the second heat exchanger; a fourth vessel connected to the reaction vessel for receiving reaction products produced in the reaction vessel; and a passage element connected to the fourth vessel for returning the heating medium from the second heat exchanger to the third vessel.