To properly continue scanning though an interlock function operates, in an X-ray computer tomography unit provided with the interlock function.

This X-ray computer tomography unit is provided with an X-ray tube 10, an X-ray detector 11, a reconstituting unit 36 for reconstituting tomography data base on multi-directional projection data detected by the X-ray detector, a high voltage generator 21 for applying high voltage to the X-ray tube 10, and an interlock control part 4 for monitoring the state of the X-ray tube multilaterally extending plural abnormal situations and stopping the applying of the high voltage at the time of judging that at least one of them occurs. The control part 4 restarts the applying of the high voltage when the stoppage of the applying of the high voltage is caused only by an abnormal situation being abnormal discharge where the rapid increase of a tube current and the rapid drop of a tube voltage are caused mainly by the deterioration in the degree of vacuum in the X-ray tube.