In a cross polarization interference eliminating apparatus, a signal demodulating section receives a first signal resulting from one of radio signals, which are transmitted in a modulated, decoded and equalized form from respectively using two kinds of polarized plain waves intercrossing at right angles in a common frequency band, and analog-to-digital converts, demodulates and equalizes the received first signal to output a first baseband signal, and an interference eliminating section receives a second signal resulting from the other radio signal, analog-to-digital converts the received digital signal to obtain a digital signal, delays the obtained digital signal. And an adding section adds the second baseband signal from the interference eliminator to the first baseband signal from the signal demodulator to output a composite signal. With this arrangement, it is possible to vary the amount of delay without a cell breathing and in accordance with the change of environment, such as temperature, without requiring the manipulation by an operator even during operation of the system. The apparatus can be compact in size and can be stabilized in operation without making an adjustment.