Reverse osmosis membrane element and water treatment device

The utility model relates to a reverse osmosis membrane element and a water treatment device. The reverse osmosis membrane element comprises a central tube and a reverse osmosis unit arranged on the outer layer of the central tube; the reverse osmosis unit comprises a composite reverse osmosis membrane layer wound on the tube wall of the central tube; the reverse osmosis membrane layer comprises a first composite membrane layer, a first runner cloth layer, a second composite membrane layer and a second runner cloth layer which are connected in sequence; the first composite membrane layer comprises a first reverse osmosis membrane layer and a second reverse osmosis membrane layer which are oppositely arranged on a desalting layer surface, and a third flow channel cloth layer arranged between the first reverse osmosis membrane layer and the second reverse osmosis membrane layer; the second composite membrane layer comprises a third reverse osmosis membrane layer and a fourth reverse osmosis membrane layer which