PROBLEM TO BE SOLVED: To provide an image display device which generates and displays a reference image on the basis of a three-dimensional image so that an object domain which is included in an anatomical structure and cannot be visually recognized directly in a two-dimensional image representing the anatomical structure can be preferably grasped.SOLUTION: An image display device acquires a three-dimensional image and a two-dimensional image representing the surface of an anatomical structure, acquires the corresponding imaging position and the corresponding imaging direction of the three-dimensional image corresponding to the imaging position and the imaging direction of the acquired two-dimensional image, generates a pseudo three-dimensional image representing the surface of the anatomical structure of the three-dimensional image, generates an additional three-dimensional image obtained by three-dimensionally deforming the three-dimensional image in a direction orthogonal to the corresponding imaging direction on the basis of the deformation information representing a deformation amount for deforming the pseudo three-dimensional image so that the pseudo three-dimensional image and the two-dimensional image are aligned with each other, generates the reference image which is the pseudo three-dimensional image displayed so that the object domain can be visually recognized, and performs comparative display or overlap display of the two-dimensional image and the reference image.
