An image processing device includes an image receiving section that receives two medical images, which are imaged at different imaging times, of a same examination object; a time difference acquiring section that acquires a difference between the imaging times of the two images; a global matching section and a local matching section that execute a matching process for the two medical images upon setting of a parameter value. The matching process causes the two images to match each other by moving and deforming one of the two images. The amount of the movement or the deformation necessary for matching is in an application range that is dependant on the parameter value. Also provided is a parameter setting section that sets a value corresponding to the difference between the imaging times acquired in the time difference acquiring section to the processing section as the parameter value.