An image display system has a capsule endoscope for capturing an in-vivo image of a subject, a receiving device for receiving the in-vivo image from the capsule endoscope, and an image display apparatus for displaying a group of in-vivo images of the subject. The capsule endoscope has an imaging unit having an optical light-shielded black region in an effective pixel region contributing to image capture. By the imaging unit, an in-vivo image including the signal level of the black region is detected. The receiving device receives an image signal of the in-vivo image. The image display apparatus obtains an in-vivo image group from the receiving device. The image display apparatus does not display an in-vivo image in the in-vivo image group determined as an image influenced by fluctuations in the power source voltage but displays a stable in-vivo image which is not influenced by fluctuations in the power source voltage.
