Microwave-induced high dc voltage of a few millivolts across the unbiased BaPb0.7Bi0.3O3 Josephson tunnel junction array is observed. A nearly rectangular hysteresis loop due to the voltage generation appears in current-voltage curve. The loop depends on load resistance, rf power and length and width of the sample. The induced voltage polarity can be easily switched by an external pulse current input signal of only 50 A/cm2. This voltage switching can probably be exploited in the Josephson junction array as a future element.