Disclosed is an X-ray tube that has a simple configuration and is capable of irradiating multiple different X-rays while switching them at a high rate, as well as an X-ray CT device using the X-ray tube. The X-ray tube comprises first and second electron generators, a deflection means, and a target. The deflection means switches the direction in which first and second electron beams are transmitted between first and second directions. The target comprises first, second, third, and fourth surfaces. The first surface receives a first electron beam transmitted toward the first direction and irradiates a first X-ray toward the irradiation field. The second surface receives a second electron beam transmitted toward the first direction and irradiates a second X-ray toward a direction different from the irradiation field. The third surface receives a first electron beam transmitted toward the second direction and irradiates the first X-ray toward a direction different from the predetermined irradiation field. The fourth surface receives a second electron beam transmitted in the second direction and irradiates the second X-ray toward the irradiation field.
