A spiral membrane element that can reduce the dimension increase in the length direction is provided. Also, a method for producing a spiral membrane element is provided having a step of forming a fiber reinforced resin layer having a reinforcing fiber layer and a strengthening fiber layer. The spiral membrane element is provided with a cylindrical wound body in which a separation membrane, a feed-side channel material, and a permeate-side channel material in a laminated state are wound in a spiral form around a center tube having a hole, and a sealing part for preventing feed-side fluid and permeate-side fluid from being mixed with each other, wherein a fiber reinforced resin layer having a reinforcing fiber layer and a strengthening fiber layer enclosed and buried with the same resin is provided on an outer circumferential side of the cylindrical wound body.