In order to examine the possibility of applying newly developed porous fine ceramics to aerostatic guides, the static stiffness of an externally pressurized gas thrust bearing made of the porous fine ceramics was investigated. The area and center-to-center distance of pores were analyzed with image processing technique. 60% of the pores of the tested fine ceramics were of 40μm in diameter and the mean center-to-center distance was 85.4μm. The dimensionless static stiffness of the tested porous fine ceramics was 0.45-0.6 at a bearing clearance around 5μm. The tested porous fine ceramics would be applied to aerostatic guides.