HOLLOW FIBER MEMBRANE MODULE AND DEHUMIDIFIER/HUMIDIFIER

A hollow fiber membrane module includes an inner case with a one-end-side outer peripheral surface , the width of which is constant from one end side toward the other end side, and an other-end-side outer peripheral surface which gradually widens from one end side toward the other end side, and in the inner case , a hollow portion that opens to the other end side is provided on an inside of the other-end-side outer peripheral surface and a plurality of windows that allow communication between the hollow portion and the annular gap are provided, and in the outer case , a communication hole that communicates between the annular gap and the outside of the outer case is provided at a position that is closer to the one end side.