An ultrasound observation device includes a feature data calculation unit that calculates feature data of an ultrasound signal by analyzing the ultrasound signal, an attenuation rate setting unit that divides an area of interest preliminarily set on the ultrasound image into a plurality of sections and sets an attenuation rate giving attenuation characteristics to ultrasound propagating through an observed target based on the feature data calculated by the feature data calculation unit for each of the sections, an attenuation rate correction unit that corrects the attenuation rate in a range including at least a boundary between adjacent sections in a manner smoothly changing across the adjacent sections, and a feature data correction unit that performs attenuation correction on the feature data using the attenuation rate corrected by the attenuation rate correction unit to calculate correction feature data.
