A rapid change in brightness of a captured image due to a disturbance is suppressed. An acquisition unit that acquires a detection result of brightness of an image of a subject in a living body, and an exposure of an imaging unit according to a first period in which the detection result of brightness indicates a value within a predetermined range. And a control unit that determines a second period for maintaining the exposure corresponding to the value included in the range. [Selection] Figure 3【課題】撮像される画像の、外乱に伴う明るさの急激な変化を抑止する。【解決手段】生体内における被写体の像の明るさの検知結果を取得する取得部と、前記明るさの検知結果が所定の範囲内の値を示す第１の期間に応じて、撮像部の露出を、前記範囲内に含まれる値に対応する露出に維持する第２の期間を決定する制御部と、を備える、医療用観察装置。【選択図】図３
