PURPOSE: To attain the measurement with a small error by fitting each antenna to a transmitter and a receiver, obtaining a delay spread value according to a specific equation from a delayed profile through transmission reception of a radio wave and using the corrected delay spread as a measurement value.

CONSTITUTION: A radio wave whose input level is known is given to a receiver to generate a calibration curve. Then a transmitter and the receiver are connected directly with a cable to measure a delayed profile of a transmission waveform. Then the delayed profile is sampled and the level is calibrated, then the delay spread So is obtained, Then an antenna is connected respectively to the transmitter and the receiver and the delayed profile is obtained by sending/receiving the radio wave to the antennas. Similarly the level is calibrated to obtain a delay spread Sm. The delay spread Sm is corrected by the delay spread So according to equation I to obtain a corrected value Sc. Thus, the measurement error is reduced.