A filter device includes: a shaft having an intermediate coil wire between a proximal filter wire and a distal filter wire； a proximal filter on the proximal filter wire； and a distal filter on the distal filter wire. The intermediate coil wire is disposed to extend between downstream and upstream blood vessels to pass through a path of placement that leads to another downstream blood vessel. Both the filters have a contracted configuration for being delivered into the blood vessel and an expanded configuration for capturing an embolus inside the blood vessel. The proximal filter is oriented such that an inlet opening, for taking in the embolus, of a proximal filter body in the expanded configuration faces the distal side, and the distal filter is oriented such that an inlet opening, for taking in the embolus, of a distal filter body in the expanded configuration faces the proximal side.
