An X-ray generator

An X-ray generator 1 has: an electron gun 3 to emit an electron beam; a target unit T; a coil part 9 capable of deflecting the travelling path of the electron beam; a detector 31 to detect electrons reflected from the target unit T; and a controller 33 to control the coil part 9 on the basis of a detection signal from the reflected electron detector 31. The target unit T comprises a substrate (21, Figure 2), and a target body (23) buried in the substrate (21). The diameter of an irradiation area of the electron beam on the target unit T is larger than the diameter of the target body 23. The controller 33 controls the coil part 9 to two-dimensionally scan the irradiation area on the target unit T so that the target body 23 is always included in the irradiation area of the electron beam on the target unit T. Alternatively, the detection signal used to control deflection of the electron beam may be obtained from an X-ray detector (41, Figure 26) or a target current detector (51, Figure 27).