Air filter

An air filter may include a bellows made of an air-permeable filter medium, which is folded in a longitudinal direction to form a plurality of folds, for filtering air, and a supporting frame for supporting the bellows. The supporting frame may be a substantially closed comb-like ring having a plurality of supporting teeth. At least two supporting teeth adjacent in the longitudinal direction may fix at least two folds of the bellows also adjacent in the longitudinal direction to a predefined distance from each other. The comb-like ring may include two fold blades and two outer bands connecting the fold blades. The fold blades may be inserted in a transverse direction running transversely to the longitudinal direction into respective end folds of the bellows. The two outer bands may have the supporting teeth, including high supporting teeth and low supporting teeth.