An x-ray emitting window is formed at a front end face, and a taper surface tilted with respect to the x-ray emitting direction is formed near the emitting window, whereby an object to be inspected can be prevented from abutting against the front end face even if the object is pivoted about an axis intersecting the emitting direction while the object is disposed closer to the x-ray emitting window. As a consequence, while the object is disposed closer to the x-ray emitting position, the orientation of the object can be changed. Therefore, when inspecting the internal structure of the object and the like by irradiating the object with x-rays and detecting the x-rays transmitted through the object, not only a magnified penetration image of the object with a high magnification rate is obtained, but also the internal structure of the object and the like can be verified in detail by changing the orientation of the object.