A shadow region extraction method capable of extracting a shadow region from contrast enhanced three-dimensional images obtained at different time points in an improved manner. The method includes the steps of detecting a first shadow region from a contrast enhanced two-dimensional image constituting a contrast enhanced three-dimensional image obtained at a first time point among a plurality of contrast enhanced three-dimensional images of a subject obtained at different time points, detecting, by the use of position information of a point in the first shadow region, a second shadow region corresponding to the first shadow region from a contrast enhanced two-dimensional image constituting a contrast enhanced three-dimensional image obtained at a second time point different from the first time point, and displaying the first shadow region and the second shadow region.