A spiral separation membrane element comprising: a water collection tube; an envelope-like membrane which is formed by using two separation membranes wound around the water collection tube, each of the membranes having a feed-side surface and a permeate-side surface, and including a band-shaped region (33, 34) on at least one end of the feed-side surface in an axial direction of the water collection tube, wherein the "end" provided with the band-shaped region (33, 34) refers to a region within 20% of the width of the separation membrane in the axial direction of the water collection tube from an edge of the separation membrane in the axial direction of the water collection tube wherein the separation membranes are overlaid on each other so that the permeate-side surfaces face inward, and are arranged such that the feed-side surfaces are opposed to each other, or an envelope-like membrane which is formed by using one separation membrane wound around the water collection tube, the membrane having a feed-side surface and a permeate-side surface, and including a band-shaped region (33, 34) on at least one end of the feed-side surface in an axial direction of the water collection tube, wherein the "end" provided with the band-shaped region (33, 34) refers to a region within 20% of the width of the separation membrane in the axial direction of the water collection tube from an edge of the separation membrane in the axial direction of the water collection tube, wherein the separation membrane is folded so that permeate-side surfaces of the separation membrane face inward, and is arranged such that feed-side surfaces of the separation membrane are opposed to each other; a channel material fused to the band-shaped region (33, 34), wherein the channel material comprises a plurality of resin bodies arranged by fusion at intervals in the band-shaped region (33, 34), and wherein the channel material is arranged such that the resin bodies provided on the feed-side surfaces opposed to each other are overlaid on each other so as to cross one another, wherein the plurality of resin bodies are arranged in the form of stripes. a water collection tube; an envelope-like membrane which is formed by using two separation membranes wound around the water collection tube, each of the membranes having a feed-side surface and a permeate-side surface, and including a band-shaped region (33, 34) on at least one end of the feed-side surface in an axial direction of the water collection tube, wherein the "end" provided with the band-shaped region (33, 34) refers to a region within 20% of the width of the separation membrane in the axial direction of the water collection tube from an edge of the separation membrane in the axial direction of the water collection tube wherein the separation membranes are overlaid on each other so that the permeate-side surfaces face inward, and are arranged such that the feed-side surfaces are opposed to each other, or an envelope-like membrane which is formed by using one separation membrane wound around the water collection tube, the membrane having a feed-side surface and a permeate-side surface, and including a band-shaped region (33, 34) on at least one end of the feed-side surface in an axial direction of the water collection tube, wherein the "end" provided with the band-shaped region (33, 34) refers to a region within 20% of the width of the separation membrane in the axial direction of the water collection tube from an edge of the separation membrane in the axial direction of the water collection tube, wherein the separation membrane is folded so that permeate-side surfaces of the separation membrane face inward, and is arranged such that feed-side surfaces of the separation membrane are opposed to each other; a channel material fused to the band-shaped region (33, 34), wherein the channel material comprises a plurality of resin bodies arranged by fusion at intervals in the band-shaped region (33, 34), and wherein the channel material is arranged such that the resin bodies provided on the feed-side surfaces opposed to each other are overlaid on each other so as to cross one another, wherein the plurality of resin bodies are arranged in the form of stripes.