A method for aralkylation of benzene or alkylbenzenes which is characterized in that an aromatic olefin having a double bond or double bonds which are conjugated with the benzene ring is added to the benzene or alkylbenzenes in the presence of at least one member of catalyst selected from the group consisting of the compounds represented by the general formula: CnF2n+1-mClmSO3H in which the symbol n is an integer from 1 to 5 and m is 0 or 1. Since the selectivity to the aromatic olefin in the reaction is excellent, the mixture of aromatic olefins and aliphatic olefins can be employed as one of the starting material.
