In a process for producing an alkenylbenzene by the reaction of an alkylbenzene having 8 or more carbon atoms and a conjugated diolefin, the improvement in which the reaction is performed in the presence of a catalyst obtained by dispersing (a) an alkali metal and (b) potassium carbonate and/or potassium hydroxide in the presence of (c) an aromatic hydrocarbon having at least a substituent with a double bond.