An object of the present invention is to provide a filter device that makes it possible to change the position of a filter easily when the filter device is used together with an atherectomy device and that makes it possible to efficiently capture emboli. The present invention provides a filter device, including: a core member； a push member； a first tube； a second tube； a third tube； a first restriction member disposed on the first tube and configured to restrict a pushing movement of the third tube to the distal direction； a filter； a ring fixed to the opening； first wires； and second wires； wherein the filter is configured in such a manner that the diameter of the opening is reduced by deformation of the shape of the ring, the deformation being caused by the first wires and the second wires when the push member fixed to the core member is pushed with the push member in contact with the second tube, and in such a manner that the diameter of the opening is expanded by restoration of the ring to the original shape, the restoration being caused by separating the push member fixed to the core member from the second tube.
