The microwave reflectometer system in the GAMMA 10 central cell has been recently upgraded using PIN diode switches and an axial array of transmitting and receiving horn antennas to investigate internal structures of ICRF waves. The system successfully worked to measure high-frequency density fluctuations accompanied by ICRF waves at multi axial locations in a single discharge. By using several discharges for radial scan with the axial antenna switching, radial and axial measurement of the density fluctuations was achieved. Obtained profiles of 6.36 MHz ICRF wave for ion heating show axial variation in those intensity, suggesting the effect of cyclotron damping. Furthermore, in accordance with the unexplained variation of diamagnetism before the main ramp-up, the intensity near the ICRF antenna is found to also vary in time. The developed system is useful to study the behavior of ICRF waves inside a hot plasma.