An ultrasound observation device includes a controller. The controller is configured to: calculate feature data of an ultrasound signal by analyzing the ultrasound signal; divide an area of interest preliminarily set on an ultrasound image into a plurality of sections; and set an attenuation rate for each of the sections; correct the attenuation rate in a range including at least a boundary between adjacent sections in a manner smoothly changing across the adjacent sections; and perform attenuation correction on the feature data using the corrected attenuation rate to calculate correction feature data.