To provide a blood treatment filter device capable of efficiently utilizing a blood treatment filter. A blood treatment filter device 20 has a filter sheet 26 through which a specific component among components forming blood is harder to pass than other components and a spacer sheet 27 through which the specific component is easier to pass than through the filter sheet 26. The filter sheet 26 has filter through-holes 39 disposed at intervals. The filter sheet 26 and the spacer sheet 27 are spirally wound in an overlapped state. The filter device 20 has seals 31 sealing both end portions in the longitudinal direction of a wound body 25 formed by the filter sheet 26 and the spacer sheet 27 which are spirally wound in a fluid-tight manner. The outer peripheral surface of the wound body 25 is formed by the filter sheet 26.
