Аннотация:The data of the photoelectrical UBV-observations of the X-ray pulsar V725 Tau (= A0535+26) are presented. A high correlation (r = 0.94) of the slow optical variability, pulsar period, and average X-ray flux at the quiescent state have been established as the result of the comparison of all available photometric (since 1973) and X-ray data. It is concluded that the X-ray activity of the object is related with the Be-star's mass loss enhancement, which corresponds to gradual increase of brightness since 1965.