The present invention provides a foam dispensing unit (10) that dispenses a content liquid in a foamed state by causing the content liquid pumped out via a liquid flow channel (23) to pass through a porous member (29) provided in a foaming flow channel (24) together with air, the foam dispensing unit including a mechanism for variably positioning a passage surface (40), the mechanism rotatably holding the porous member (29) in the foaming flow channel (24) to variably position a content liquid passage surface of the porous member (29). The mechanism for variably positioning a passage surface (40) includes a loosely holding region (41) formed in the foaming flow channel (24) and the porous member (29) loosely mounted in the loosely holding region (41). The porous member (29) has a spherical shape, and freely rotates inside the loosely holding region (41) due to an action of a stream of the content liquid passing through the loosely holding region (41), so as to replace a surface thereof in a pass-through direction.