A calibrating apparatus includes a first reproducer which reproduces a reference image representing a state in which a plane is overlooked, along an X axis and a Y axis orthogonal to each other. A second reproducer reproduces a scene image outputted from a camera that captures the plane, along a U axis and a V axis orthogonal to each other. An acceptor accepts a designating manipulation of designating a first area of an X-Y coordinate system, in association with a reproducing process of the first reproducer. A first calculator calculates a second area of a U-V coordinate system corresponding to the first area designated by the designating manipulation, by referring to a calibration parameter indicating a corresponding relationship between the X-Y coordinate system and the U-V coordinate system. A definer defines the second area calculated by the first calculator, in association with a reproducing process of the second reproducer.