To eliminate necessity to exchange an X-ray detector itself or a detection substrate, or to reduce exchange frequency when a channel is broken in an X-ray computerized tomograph.

This X-ray computerized tomograph is provided with an X-ray tube 101 for irradiating an examinee with X-rays, a multi-channel X-ray detector 103 for detecting X-rays transmitted through the examinee, a reconstruction device 114 for reconstructing tomographic image data from projection data, a display device 119 for displaying the reconstituted tomographic image data, a decision part 113 for deciding the presence/absence of a fault in the respective channels of the X-ray detector and a data replacement part 117 for replacing the data of a fault channel decided as the presence of the fault by the decision part with replacement data obtained from the data of a plurality of channels in the vicinity of the fault channel.