An X-ray CT system as the embodiment comprises an annular rotating body configured to accommodate an X-ray tube, the rotating body having a central opening, into which a bed can be inserted in the center thereof, a cover shaped in a tubular form and having a tubular case part, which, when fitted in the opening, shields the annular rotating body from a central side of the opening, the cover being provided with an X-ray transmission opening at the tubular case part, through which, X-rays from the X-ray tube are allowed to transmit, and two sheet-like soundproof members configured to sandwich a soundproof layer, the soundproof members being disposed to to close the X-ray transmission opening. According to the X-ray CT system, it is possible to reduce sufficiently the noise leaking from inside the cover.
