An ultrasound observation apparatus includes: a feature calculation unit configured to calculate a plurality of features based on the ultrasound signal； a feature image data generation unit configured to generate feature image data in which a feature of a display target to be displayed together with the ultrasound image, among the plurality of features calculated by the feature calculation unit, are colorized with a predetermined display specification； and a display specification setting unit configured to set at least one of a colorization range of the feature of the display target and a change rate of hue of the feature of the display target, which are display specifications of the feature of the display target, by comparing a representative value of other feature other than the feature of the display target with a threshold value.
