The present invention relates to an X-ray tube, having a structure enabling capturing of a clear magnified transmission image and enabling increase of a magnification factor of the magnified transmission image, and an X-ray source including the X-ray tube. In the X-ray tube, X-rays are generated by making electrons from an electron gun incident onto an X-ray target of an anode, disposed inside an anode housing unit, and the generated X-rays are taken out from an X-ray emission window. In particular, the anode housing unit has a pair of conductive flat portions disposed parallel to a reference plane, orthogonal to an electron incidence surface of the X-ray target, and so as to sandwich the X-ray target. The reference plane contains a first reference line, joining an electron emission exit center of the electron gun and an electron incidence surface center of the X-ray target, and a second reference line, being a straight line intersecting the first reference line on the electron incidence surface of the X-ray target and joining the electron incidence surface center and an X-ray emission window center.