To provide a simple and industrial production method by which high activity and high selectivity are retained and high boiling point material content is reduced, in the method for producing a cyclododecatriene by trimerizing butadiene.

The method for producing the cyclododecatriene comprises using a catalyst obtained by mixing (1) a hydrocarbon solvent containing a compound represented by the general formula: TiX4 (X is at least one halogen atom selected from a group belonging to the group VII of the periodic table) with (2) a hydrocarbon solvent containing a compound represented by the general formula: AlRmXn (R is a 1-4C alkyl group; X is one halogen atom which is the same as mentioned above; 1≤m and n≤2 and m+n=3) and obtained by accompanying water in an amount of 0.1-10 mol based on 1 mol compound represented by the general formula: AlRmXn by an inert gas.