An image acquisition unit acquires a brain image of a subject. A cisternal region extraction unit extracts a cisternal region from the brain image by performing registration between a standard brain image and the brain image. Then, a bleeding region specifying unit specifies a bleeding region based on a first signal value distribution, which is the signal value distribution of the cisternal region extracted from the brain image, and a second signal value distribution, which is the signal value distribution of a cisternal region of the standard brain image.