A high brightness X-ray generator and a high brightness X-ray generating method are provided which are able to promote an increase in X-ray brightness (i.e., an increase in an X-ray output) while suppressing an excessive increase in the cost of optical elements such as a laser unit, a mirror, and a lens. A high brightness X-ray generator generates an X-ray by inverse Compton scattering by colliding an electron beam with pulse laser light. There are provided a plurality of pulse laser units (32A, 32B) which emits a plurality of pulse laser lights (3a, 3b ) in predetermined periods, an optical-path matching unit (34) which matches optical paths of the plurality of pulse laser lights, and a timing control unit (40) which controls timings of the optical-path matching unit and the pulse laser units, wherein the plurality of pulse laser lights is emitted from the same optical path at different timings.