Heat dissipation of a target is enhanced in a transmissive X-ray generating apparatus where an anode member constitutes a part of a container. An anode member configured to hold a target is divided into an outer anode member, which is configured to hold the target and is connected to a container, and an inner anode member, which is joined to an insulating tube and is closer to an electron emitting portion than the outer anode member is. The outer circumferential surface of the inner anode member is joined to the outer anode member via a joining member. Heat generated by the electron emitting portion is dissipated mainly from the inner anode member via the insulating tube, or directly, to an insulating liquid.
