[Problems to be Solved]Enabling confirmation of a local abnormality of lungs along with a three-dimensional motion of lungs during respiration.[Means for Solving the Problems]The region extraction unit (14) extracts lung regions from three-dimensional images (Vi) of a plurality of time phases, the alignment unit (16) aligns pixel position in the lung region extracted from each three-dimensional image (Vi) between the three-dimensional images (Vi) . This calculates a displacement vector field at each time phase of the three-dimensional images (Vi). The function generation unit (18) calculates a local ventilation volume function representing a temporal change in ventilation volume at each point in the displacement vector field, and the quantification unit (20) calculates a difference function, which is a function of difference values between the local ventilation volume function and benchmark ventilation volume function, as a quantitative value representing a difference between the local ventilation volume function and the benchmark ventilation volume function. The display control unit (22) displays lung VR images on which the difference function is mapped on the display (4) in time series order.
