An ultrasonic observation apparatus includes an ultrasonic probe for transmitting an ultrasonic signal to a specimen and receiving an ultrasonic wave reflected from the specimen, a frequency analysis unit for calculating a frequency spectrum by analyzing a frequency of the ultrasonic wave received by the ultrasonic probe (2), a feature-data extraction unit for extracting at least one piece of feature data from the frequency spectrum by approximating the frequency spectrum calculated by the frequency analysis unit, and a feature-data image data generation unit for generating feature-data image data that displays information corresponding to the feature data in accordance with one of a plurality of display methods depending on a relationship between the feature data extracted by the feature-data extraction unit and a threshold in the feature data, the threshold being constant regardless of a value of a display parameter which the image data has.
