An element unit comprising: shafts; a plurality of separation membrane elements each including a separation membrane pair having two flat separation membranes (6, 6) disposed so that permeate-side surfaces of the separation membranes (6, 6) face each other and a water collecting flow path provided between the separation membranes (6, 6), and a sealed portion that seals the separation membranes (6, 6) at peripheral edge portions of the separation membranes (6, 6); a suspension portion (8, 51, 52) that suspends the separation membrane elements on the shaft; and a water collection nozzle that provides communication between the water collection flow path and an outside of the separation membrane elements wherein each of the separation membrane elements comprises a resin portion that adheres to both the permeate-side surfaces of the separation membrane pair (6, 6) facing each other so that a predetermined space of 500 μm to 5000 μm is secured which forms the water collection flow path, wherein the resin portion is in a dot shape, a linear shape or a grid shape, wherein a projected image of the resin portion on the separation membranes (6, 6) is discontinuous, wherein in the separation membrane pair (6, 6), an outward side that is more outward in a planer direction of the separation membranes (6, 6) than the water collection flow path is provided with a through-hole through which a shaft is able to extend, and wherein the through hole functions as the suspension portion (8, 51, 52), and wherein through-holes 8 are disposed at four locations near end portions or near corner portions of each separation membrane element 1. shafts; a plurality of separation membrane elements each including a separation membrane pair having two flat separation membranes (6, 6) disposed so that permeate-side surfaces of the separation membranes (6, 6) face each other and a water collecting flow path provided between the separation membranes (6, 6), and a sealed portion that seals the separation membranes (6, 6) at peripheral edge portions of the separation membranes (6, 6); a suspension portion (8, 51, 52) that suspends the separation membrane elements on the shaft; and a water collection nozzle that provides communication between the water collection flow path and an outside of the separation membrane elements wherein each of the separation membrane elements comprises a resin portion that adheres to both the permeate-side surfaces of the separation membrane pair (6, 6) facing each other so that a predetermined space of 500 μm to 5000 μm is secured which forms the water collection flow path, wherein the resin portion is in a dot shape, a linear shape or a grid shape, wherein a projected image of the resin portion on the separation membranes (6, 6) is discontinuous, wherein in the separation membrane pair (6, 6), an outward side that is more outward in a planer direction of the separation membranes (6, 6) than the water collection flow path is provided with a through-hole through which a shaft is able to extend, and wherein the through hole functions as the suspension portion (8, 51, 52), and wherein through-holes 8 are disposed at four locations near end portions or near corner portions of each separation membrane element 1.