A disc filter includes several triangular sectors that are connected from their neck section to the body of the disc filter. The sectors form a relatively thin disc that is rotated during filtration in a basin that contains a suspension to be filtered. The side surfaces of the sector have openings through which liquid in the suspension passes into several essentially radial flow channels inside the sector to flow on to the neck section and away from the sector. A separating wall is formed between two adjacent radial flow channels. Furthermore, the sector is made of two side elements, which are of plastic material and the mating surfaces of which are placed against each other.