Provided is a reverse osmosis treatment apparatus which decreases operation power by utilizing a back pressure caused by regulating an amount of permeated water. The reverse osmosis treatment apparatus includes a first pressure vessel for a primary treatment of untreated water, and a second pressure vessel for a secondary treatment of the water treated by the primary treatment, wherein a reverse osmosis membrane element having a reverse osmosis membrane or the plurality of reverse osmosis membrane elements are arranged in series along a water collection pipe in the first pressure vessel and the second pressure vessel. The first pressure vessel includes a first outlet pipe which discharges permeated water, and a permeated water flow control valve connected to the first outlet pipe and regulating a pressure in the first pressure vessel. An energy recovery apparatus is provided between the first outlet pipe and the permeated water flow control valve.