The kinetic study on the bromine-exchange reaction of antimony tribromide with ${alpha}$-phenylethyl bromide in nitrobenzene has been carried out, using Br-82 labelled antimony tribromide. The results show that the exchange reaction is first order with respect to ${alpha}$-phenylethyl bromide, and either second or first order with respect to antimony tribromide depending on its concentration. It is also concluded that ${alpha}$-phenylethyl bromide exchanges bromine atom with antimony tribromide much faster than other organic bromides previously examined. Reaction mechanisms for the exchange reaction are discussed.