An x-ray generating apparatus comprises: a vacuum container having a main body, and a moving member coupled movably and airtightly to the main body via a vacuum bellows; and a guide mechanism, provided on an outer side of the vacuum container, for regulating the movement and inclination of the moving member in an approaching/separation direction with respect to an electron gun. The guide mechanism includes a guide portion where a guide flat surface along a plane orthogonal to a central axis of the electron beam is formed, the guide portion being provided on the main body side, a guided portion where a guided flat surface facing the guide flat surface is formed, the guided portion being provided on the moving member side, and at least three rolling elements placed between the guide flat surface and the guided flat surface.

An x-ray generating apparatus comprises: a vacuum container having a main body, and a moving member coupled movably and airtightly to the main body via a vacuum bellows; and a guide mechanism, provided on an outer side of the vacuum container, for regulating the movement and inclination of the moving member in an approaching/separation direction with respect to an electron gun. The guide mechanism includes a guide portion where a guide flat surface along a plane orthogonal to a central axis of the electron beam is formed, the guide portion being provided on the main body side, a guided portion where a guided flat surface facing the guide flat surface is formed, the guided portion being provided on the moving member side, and at least three rolling elements placed between the guide flat surface and the guided flat surface.