Disclosed are an X-ray tube device having a structure enabling easy manufacture of the same and an X-ray CT device with the X-ray tube device. The X-ray tube device provided with an X-ray tube for generating X-rays and a vessel accommodating the X-ray tube is characterized in that the vessel is made up of a plurality of division vessels made by dividing the vessel in a direction along the axis of the X-ray tube and in that the division vessels have cylindrical shapes having circumferential inner surfaces. The X-ray CT device is provided with the X-ray tube device, an X-ray detector so disposed as to face the X-ray tube device and used to detect X-rays transmitted through a subject, a rotary disk mounted with the X-ray tube device and the X-ray detector and rotating around the subject, an image reconstructing device for reconstructing a tomogram of the subject according to the amount of X-rays transmitted and detected by the X-ray detector at a plurality of angles, and an image display device for displaying the tomogram reconstructed by the image reconstructing device.