Humidifier

The utility model relates to a humidifier. The passage forming member (9) includes a first support rib and a first passage rib (18) that protrude from the bottom plate (16) toward the first surface (10a) of the water vapor permeable membrane (10). The first support rib forms a wet gas passage (22). The first passage rib (18) is provided with: a separation section that creates a gap between the separation section and the first surface (10a); and a clamping part (18b) which is in contact with the first surface (10a) at a position corresponding to the inlet (22a) and the outlet of the wet gas passage (22). The passage forming member (9) includes a second support rib (19) and a second passage rib that protrude from the bottom plate (16) toward a second surface (10b) of the water vapor permeable membrane (10). The second support rib (19) forms a dry gas passage. The second passage rib includes: a separation portion that generates a gap between the separation portion and the second surface (10b); and a clamping par