The objective of the present invention is to provide a spiral-type separation membrane element having superior oxidant resistance relative to the prior art, and a salt-blocking rate that tends not to decrease. The spiral-type separation membrane element is characterized in including: a supply-side flow-path material; a composite semipermeable membrane in which a skin layer is formed on the surface of a porous support, the skin layer containing a polyamide resin obtained by interfacial polymerization of a polyfunctional amine component and a polyfunctional acid halogen component; and a permeation-side flow-path material, wherein the polyfunctional amine component contains N,N′-dimethyl-meta-phenylenediamine and the permeation-side flow-path material has a porosity of 40 to 75%.