Among the planetary nebulae showing noticeable long-time variations of brightness (see our foregoing contributed paper; Astron. Circ. USSR, No. 1430, 3, 1986, and earlier publications) the young stellar planetary IC 4997 is the most prominent. Our photoelectric observations revealed its rather surprising behaviour. During 1968–85 its total UBV-brightness was monotonously decreasing, especially in filter V: the reduction of the value Δv amounted ∼ 0m.5–0m.6. The colour indices of the planetary showed that during the observation period the object as a whole, became definitely bluer. In 1985–86 our observations revealed an unexpected stop of mentioned brightness decrease, but in 1987 the object appeared to start brightening.