An ultrasound observation apparatus includes: a calculation unit that calculates features of frequency spectra obtained by analyzing a frequency of an ultrasound signal a setting unit that uses each attenuation factor candidate value per unit length and per unit frequency that give different attenuation characteristics, in each divided region obtained by dividing an ultrasound image, to perform attenuation correction on the features of the frequency spectra for removing an influence of ultrasound, and thereby calculates a preliminarily corrected feature of each frequency spectrum for each attenuation factor candidate value, and sets an optimum attenuation factor among attenuation factor candidate values and a correction unit that calculates a cumulative attenuation factor per unit frequency at a sampling point, using an optimum attenuation factor of a divided region present between a surface of an ultrasound transducer and the sampling point, and performs attenuation correction on the features using the cumulative attenuation factor.
