Adaptive sectorization is one of the solutions for the capacity decrement resulted from the unbalanced traffic due to the users having nonuniform distribution among the sectors in cellular wireless communication system. It controls the sector size adaptively and balances the number of users on service among the sectors. It is not the capacity increment but the use of maximum capacity of the cell. In this paper, we propose the adaptive sectorization algorithm that can control the sector size according to the user distribution and the structure that is designed to apply simply to the existing base station or node B.