According to one embodiment, a rotating-anode X-ray tube assembly includes a rotating-anode X-ray tube, a housing, a coolant, a first shell, an X-ray shielding member, a second shell and an air introduction unit. The first shell is provided apart from the housing and an envelope of the rotating-anode X-ray tube, and surrounds the envelope. The X-ray shielding member is provided between the first shell and the housing and apart from the housing. The second shell is provided apart from the housing to cause an airway to be formed between the second shell and the housing. The air introduction unit produces a flow of air in the airway.