In an X-ray generation apparatus of transmission type including an electron emission source, and a target generating an X-ray with collision of electrons emitted from the electron emission source against the target, the X-ray generation apparatus further includes a secondary X-ray generation portion generating an X-ray with collision of electrons reflected by the target against the secondary X-ray generation portion, and the secondary X-ray generation portion and the target are arranged such that the X-ray generated with the direct collision of the electrons against the target and the X-ray generated with the collision of the electrons reflected by the target against the secondary X-ray generation portion are both radiated to an outside. X-ray generation efficiency is increased by effectively utilizing the electrons reflected by the target.