An image display apparatus has: a first image generator that defines each position between a predetermined start point and end point of a tubular structure as a first viewpoint and generates a first image obtained by observing an image of the inside of the tubular structure from each first viewpoint toward the end point; a second image generator that defines each position between the start point and the end point as a second viewpoint and generates a second image obtained by observing an image of the inside of the tubular structure from each second viewpoint toward the start point; and a user interface that is provided with an operation part, a monitor and a display controller and is configured so that, in response to an instruction from the operation part, the display controller makes the monitor display the first image and the second image.