A displacement measuring section for measuring the displacement of the object based on ultrasonic signal (21), the elastic image generating section for generating an elastic image based on the measured displacement (22), one or more elastic images that are generated Characteristics of calculating a memory unit for storing (24), the determination region setting unit for setting the elasticity image in response to the proper image determining region of the ROI size for determining the proper image and (25), a domain characteristic of a proper image determining regions calculating section (26), the proper image determining unit for determining whether the acoustic image is proper image based on region characteristics (27), an ultrasonic observation apparatus having (1).超音波信号に基づき被検体の変位を計測する変位計測部(21)と、計測した変位に基づいて弾性画像を生成する弾性画像生成部(22)と、生成された1つ以上の弾性画像を記憶するメモリ部(24)と、適正画像判定用の適正画像判定領域をROIのサイズに応じて弾性画像に設定する判定領域設定部(25)と、適正画像判定領域の領域特性を算出する特性算出部(26)と、領域特性に基づいて弾性画像が適正画像であるか否かを判定する適正画像判定部(27)と、を有する超音波観測装置(1)。
