A spiral-wound forward osmosis membrane element (2) includes: a membrane leaf (23) in which an internal flow path extending from a first opening (26A) to a second opening (26B) is formed; and a central tube (31) around which the membrane leaf (23) is wound and which has a feed hole (31A) communicating with the first opening (26A) and a collection hole (31B) communicating with the second opening (26B). The central tube (31) has an interior partitioned to include an inflow region (3A) communicating with the feed hole (31A) and an outflow region (3B) communicating with the collection hole (31B) so that the inflow region (3A) and the outflow region (3B) each form a flow path extending continuously in an axial direction of the central tube (31) from one end to the other end of the central tube (3). Since a liquid fed into the inflow region (3A) is discharged to the outside without passing through two or more internal flow paths (26), the pressure loss in the spiral-wound forward osmosis membrane element (2) is red
