According to one embodiment, an X-ray CT apparatus is adapted to perform helical scanning on a subject placed on a couch top and perform reconstruction processing based on acquired projection data. The X-ray CT apparatus sets a first imaging range within an imaging range for the helical scanning, sets at least one of a start range and an end range in the first imaging range as a boundary range, sets a first view number for use in the reconstruction processing for a non-boundary range other than the boundary range in the first imaging range, and sets a view number for use in the reconstruction processing for the boundary range to be smaller than the first view number.
