SPIRAL MEMBRANE ELEMENT

The purpose of the present invention is to provide a spiral membrane element in which the effective membrane area of a composite semi-permeable membrane can be increased and any decrease in rejection rate due to deformation of the composite semi-permeable membrane is less likely to occur. The spiral membrane element is provided with: a laminate including a permeation-side flow path material 3, a supply-side flow path material 6, and a composite semi-permeable membrane 2 having a separation function layer on a surface of a porous support; a perforated central tube 5 around which the laminate is wound; and a sealing member 21 for preventing mixing between the supply-side flow path and a permeation-side flow path, the spiral membrane element being characterized in that the thickness of the porous support of the composite semi-permeable membrane 2 is 80 µm to 100 µm, the permeation-side flow path material 3 is formed from a tricot knit fabric, and the width of a groove that continues in a straight line is 0.05 mm to 0.40 mm.