PROBLEM TO BE SOLVED: To provide an X-ray computer tomographic apparatus capable of correcting output of a data collection unit taking into account characteristics of an X-ray detector or the data collection unit.SOLUTION: An X-ray computer tomographic apparatus includes: an X-ray tube that generates an X-ray to be irradiated on an object to be examined； an X-ray detector for detecting an X-ray that is generated from the X-ray tube and transmits the object to be examined； a data collection unit for outputting data related to the object to be examined based on an electric signal according to the intensity of the X-ray detected by the X-ray detector； reconfiguration means for reconfiguring an image based on the data output by the data collection unit； and a plurality of reference voltage sources connected to the data collection unit for generating voltages different from each other. Based on the electric signal according to the voltage generated by each of the plurality of reference voltage sources, the data collection unit corrects output data based on the electric signal according to the intensity of the X-ray detected by the X-ray detector.
