A separation membrane element comprising: a separation membrane comprising: a separation membrane main body (30, 30A, 30B) having a feed-side face and a permeate-side face; wherein the separation membrane main body (30, 30A, 30B) comprises a substrate, a porous supporting layer formed on the substrate, and a separation functional layer formed on the porous supporting layer, and a channel member located on the surface of the membrane, characterised in that the channel member being either a permeate-side channel member adhered to the permeate-side face of the separation membrane main body (30, 30A, 30B), wherein the permeate-side channel member comprises a composition containing at least a high-crystalline polypropylene and satisfies the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the permeate-side channel member has a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g, or else the channel member being a sheet channel member (42, 43, 44, 45, 46, 47) having projections (20, 21, 22, 23, 24, 25) fixed to a sheet, wherein the projections (20, 21, 22, 23, 24, 25) comprise a composition containing at least a high-crystalline polypropylene and satisfy the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the projections (20, 21, 22, 23, 24, 25) have a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g. a separation membrane comprising: a separation membrane main body (30, 30A, 30B) having a feed-side face and a permeate-side face; wherein the separation membrane main body (30, 30A, 30B) comprises a substrate, a porous supporting layer formed on the substrate, and a separation functional layer formed on the porous supporting layer, and a channel member located on the surface of the membrane, characterised in that the channel member being either a permeate-side channel member adhered to the permeate-side face of the separation membrane main body (30, 30A, 30B), wherein the permeate-side channel member comprises a composition containing at least a high-crystalline polypropylene and satisfies the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the permeate-side channel member has a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g, (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the permeate-side channel member has a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g, or else the channel member being a sheet channel member (42, 43, 44, 45, 46, 47) having projections (20, 21, 22, 23, 24, 25) fixed to a sheet, wherein the projections (20, 21, 22, 23, 24, 25) comprise a composition containing at least a high-crystalline polypropylene and satisfy the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the projections (20, 21, 22, 23, 24, 25) have a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g. (a) a content of the high-crystalline polypropylene in the composition is from 40 to 95% by weight; (b) the projections (20, 21, 22, 23, 24, 25) have a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g.