A tomography apparatus includes a data obtainer and an image processor. The data obtainer performs a tomography scan on a moving object and obtains raw data of the object The image processor reconstructs a first tomography image of the object for a first slice section in a first phase from the raw data and reconstructs a second tomography image in a second phase, which is different from the first phase, for the first slice section of the object by using the raw data. The image processor also generates motion information indicating a three-dimensional (3D) motion of the object. The second phase is a phase beyond a phase range of the raw data.