An ultrasonic observation apparatus is provided with a signal amplifier which amplifies a signal of an ultrasonic wave received from a sample with an amplification factor according to a receiving depth in order to use the signal in generating a B-mode image, a B-mode image data generator which generates B-mode image data in which the amplitude of the signal of the ultrasonic wave amplified by the signal amplifier is converted into brightness for display, an amplification corrector which performs correction to cancel the influence of the amplification by the signal amplifier in order to make the amplification factor constant with respect to the signal of the ultrasonic wave amplified by the signal amplifier regardless of the receiving depth, a frequency analyzer which calculates a frequency spectrum by analyzing the frequency of the signal of the ultrasonic wave corrected by the amplification corrector, and a feature data extractor which extracts feature data of the sample by performing an approximation process and an attenuation correction process for reducing the contribution of the attenuation occurring in accordance with the receiving depth of the ultrasonic wave and the frequency in transmitting the ultrasonic wave.
