A filtering apparatus includes a cylindrical filter F having a cylinder axis in a vertical direction, and a casing C surrounding the filter F, in which untreated water a is filtered through the filter F from an outer circumferential surface to an inner circumferential surface of the filter F, and the resulting filtered water a' is guided to the outside of the casing C. The filter F includes a plurality of divided filters arranged in the direction of the cylinder axis, and the divided filters can be easily repaired and replaced. The divided filters can be connected and integrated together via reinforcing rods 33 by using threaded connections 36, and can be individually detached. When a sealing member 38 is provided between upper and lower facing surfaces of the divided filters, the untreated water does not flow from an upper surface and a lower surface of the divided filters, and the sealing member is rotated together with the filter and does not slide. Thus, degradation of the sealing member is suppressed and a rotational driving force can also be reduced. A separable reinforcing body 40 including an intermediate support disk 42 and connecting rods 43 is preferably provided in the filter.