[Object]
To improve the productivity of a mesh filter and reduce the cost of the mesh filter while maintaining the filter performance.
[Solution]
A filter unit 4 connecting an inner cylinder 2 (gate connection part) to an outer cylinder 3 includes a plurality of longitudinal ribs formed at regular intervals orthogonally to an X-axis and in parallel with a Y-axis when a virtual plane orthogonal to a central axis 5 of the inner cylinder 2 is assumed to be an X-Y plane, a plurality of transverse ribs formed at regular intervals orthogonally to the longitudinal ribs and in parallel with the X-axis, and a plurality of rectangular openings formed between the longitudinal ribs and the transverse ribs. The longitudinal ribs are formed on one of a front side and a rear side of the filter unit 4 and the transverse ribs are formed on the other of the front side and the rear side of the filter unit 4. By injecting molten resin into to a cavity from a gate opened toward a cavity portion forming the inner cylinder 2, the inner cylinder 2, the outer cylinder 3, and the filter unit 4 are formed integrally, the rib widths of the longitudinal ribs and the transverse ribs are made constant, and the shapes of the plurality of openings are made identical.