To reduce, in an image obtained in cardiac-gated imaging by a radiation tomography apparatus, boundary artifacts while suppressing degradation of spatial resolution.There is provided a radiation tomography apparatus comprising: control means for controlling a data collection system to acquire first data by scanning a first scan region centering on a first position in a body axis direction of a subject in synchronization with heartbeats, and second data by scanning a second scan region adjacent to the first scan region and centering on a second position in the body axis direction in synchronization with the heartbeats； and reconstructing means for reconstructing an image of a slice between the first position and second position using the first and second data, the reconstructing means determining a view-angle-range-based use rate for the first data and a view-angle-range-based use rate for the second data according to a position of the slice relative to the first and second positions.
