An air cleaner is provided with: a case in which a filter element is housed and which has an opening; a cover that covers the opening of the case to be opened or closed; a hinge structure having a hinge formed to the cover and a hinge receiver formed to the case to be engaged with the hinge in a detachable manner such that the cover is pivotal around the hinge with respect to the case; and an engagement maintaining mechanism provided to side surfaces of the case and the cover so as to maintain the engagement between the case and the cover in a range in which the cover closes the case and in a range in which the cover is opened by a predetermined angle.