An ultrasound observation apparatus for generating an ultrasound image based on an ultrasound signal obtained by an ultrasound probe having an ultrasound transducer for transmitting an ultrasound wave to an observation target and receiving the ultrasound wave reflected from the observation target. The ultrasound observation apparatus includes: a frequency analysis unit that analyzes a frequency of the ultrasound signal to calculate frequency spectra depending on a reception depth and a reception direction of the ultrasound signal a frequency band setting unit that sets a frequency band used for calculating a feature of each of the frequency spectra by use of parameters associated with a frequency spectrum in each of candidate bands having different bandwidths a feature calculation unit that calculates the feature of each of the frequency spectra based on the frequency band and a feature image data generation unit that generates feature image data based on the feature.
