Provided are an air cleaning device that has a simple structure and that allows ultraviolet light to reach a wide area on the surface of an air filter material that has a pleated shape, and a dust collecting filter. The air cleaning device is provided with a dust collecting filter (3) and an ultraviolet light source (5). The dust collecting filter (3) is provided with an air filter material (6) that has a pleated shape, and a retaining member (7) that retains the shape of the air filter material (6). The retaining member (7) is provided with a base (7a) that extends in a direction intersecting with the longitudinal direction of the folds of the pleated shape, and a projection (7b) that projects from the base (7a) to the valley of the pleated shape. The ultraviolet light source (5) irradiates ultraviolet light to the retaining member (7). At least a portion of the retaining member (7) diffuses and transmits the ultraviolet light.
