Space filter, and fixation method of small filtering hole of the space filter

The invention discloses a space filter, and a fixation method of a small filtering hole of the space filter. The space filter comprises a vacuum glass tube, an incident lens and an emitting lens which are respectively arranged at the two ends of the vacuum glass tube, and the small filtering hole arranged in the vacuum glass tube, wherein the small filtering hole is disk-shaped, the thickness of the small filtering hole is gradually decreased from the edge to the center, and a hole structure used for light transmission is disposed at the circle center position of the small filtering hole. According to the invention, the small filtering hole designed by use of a novel structure, the thickness of the small filtering hole is reduced, and while the filtering effect is improved, the hole obstruction effect is reduced; the edge of the small filtering hole has a groove-like design so as to facilitate fusion splicing of the vacuum glass tube; and when the small filtering hole is processed and fixed, no matter what kind of materials the small filtering hole is made of, a crack phenomenon can always be effectively avoided.