The capsule endoscope 10 has an imaging device 13, a memory 15 for storing brightness information acquired by the imaging device 13, brightness information acquired by the imaging device 13, and immediately before acquiring brightness information. The brightness information acquired by the image sensor 13 and stored in the memory 15 is compared. If the comparison result is within a predetermined threshold, the brightness information is further acquired by the image sensor 13 and the acquired brightness information is While the comparison with the brightness information acquired immediately before by the image sensor 13 and stored in the memory 15 is further performed, if the comparison result is larger than a predetermined threshold value, the image is captured by the image sensor 13 and the captured image is displayed. A control unit 16 that stores the data in the memory 15 or controls the image transmission unit 14 provided in the capsule endoscope 10 to transmit the image to the outside of the capsule endoscope 10.カプセル型内視鏡１０は、撮像素子１３と、撮像素子１３で取得された明るさ情報を記憶するメモリ１５と、撮像素子１３で取得された明るさ情報と、明るさ情報を取得する直前に撮像素子１３で取得されメモリ１５に記憶された明るさ情報とを比較し、比較結果が所定の閾値以内の場合、さらに撮像素子１３で明るさ情報を取得するとともに、取得された明るさ情報を直前に撮像素子１３で取得されメモリ１５に記憶された明るさ情報との比較をさらに行う一方、比較結果が所定の閾値より大きい場合、撮像素子１３で画像の撮像を行い、撮像された画像をメモリ１５に記憶する、または、カプセル型内視鏡１０に設けられた画像送信部１４によってカプセル型内視鏡１０の外部に送信するように制御する制御部１６と、を有する。
