A wireless microphone includes a tubular housing having top and bottom open ends. The housing has an outer surrounding wall and an inner partition wall. The inner partition wall cooperates with an upper portion of the outer surrounding wall so as to define a battery-receiving space. A battery module is received in the battery-receiving space. A head unit is mounted on the top open end of the housing, and covers the battery module. A positioning unit is disposed at an outer surrounding surface of the battery module and an inner surrounding surface of the outer surrounding wall of the housing for positioning the battery module in the battery-receiving space.