The present invention provides an X-ray optical apparatus including an X-ray reflective structure in which at least three reflective substrates are arranged with an interval and an X-ray which is incident into a plurality of X-ray passages whose both sides are put between the reflective substrates is reflected from the reflective substrate at both sides of the X-ray passage to be parallelized and emitted from the X-ray passage. When an edge of the X-ray reflective structure is an inlet of the X-ray and the other edge is an outlet of the X-ray, a pitch of the reflective substrates at the outlet is larger than a pitch at the inlet. Therefore, it is possible to efficiently parallelize the incident X-ray to be emitted with a simple structure.