According to an aspect of the present invention, there is provided a filter including: a belt shaped frame formed of a resin, an opening being provided inside the frame; a pair of link portions formed on the frame at both distal ends thereof to be engagable with each other; and a filtering member provided in the opening, wherein the frame is formed to have a flat plate shape or a curved shape that has a center angle equal to or less than 180 degrees in a state where the pair of link portions are not engaged, and wherein a plurality of grooves are formed on at least one surface of the frame at intervals along the longitudinal direction.