This article examines some factors that should be taken into consideration as the number of arbitrators to constitute arbitral tribunal, how to select them and the characteristics of arbitrators by their expert field, and the various problems that may arise in selection of arbitrators. When dispute parties select one arbitrator or a chairman of arbitral tribunal, they should consider the characteristic of case. When legal problem is more important, they should select a lawyer, whereas when trade practice is more important, they should select a businessman. Especially, when they decide to select a businessman as one arbitrator or a chairman of arbitral tribunal, they allow him not to write the reason of award if possible because he is lack of know-how to write it. Also, dispute parties should acquire the information of the main career and character of arbitrator, his experience of arbitration and so on before they select him.