There is provided an X-ray detection system comprising a detector and a data acquisition unit. The detector detects an X-ray passing through a body being examined and producing an analog electric signal corresponding to the X-ray for each channel. The data acquisition unit includes a plurality of circuit blocks each including as many circuits as the number of channels assigned to each block. The data acquisition unit converts the analog electric signal output from the detector into a digital signal for each channel and outputting the resultant digital signal and a phase control unit controlling the phase of the circuit blocks of the data acquisition unit such that the circuit blocks are grouped into a plurality of groups and the respective groups of circuit blocks operate in synchronization with clock signals whose phase are different at least between two groups.
