A PET/MRI hybrid machine that combines a PET device with an MRI device, includes: an open PET device that has a PET field of view at least part of which is an open space accessible from outside and an open MRI device that has an MRI field of view at least part of which is an open space accessible from outside, and the open space of the PET field of view and the open space of the MRI field of view are allowed to overlap each other at least in part. This makes it possible to simultaneously measure and image the same open space accessible from outside by the PET device and the MRI device, thereby acquiring functional information and morphological information at the same time.
