<p>A drainage device comprising a generally plate-like elongated conduit member and a non-woven fabric attached to said conduit member and a non-woven fabric attached to said conduit member, said drainage device being adapted to be embedded into soil in a direction coincident with a longitudinal direction of said conduit member and for use in drawing up water existing in the soil; wherein said conduit member comprises a plurality of parallel ribs extending substantially in the longitudinal direction of said conduit member and defining conduit spaces between them and a plurality of transverse ribs extending in a transverse direction of said conduit member for connecting the longitudinal ribs together, and wherein the spacing ( l ) between the adjacent longitudinal ribs is from 0.5 mm to 5 mm.</p>
