A separation membrane element comprising: a separation membrane comprising: a separation membrane main body having a feed-side face and a permeate-side face ; wherein the separation membrane main body 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 , wherein the permeate-side channel member comprises a composition containing at least a high-crystalline polypropylene (A) and satisfies the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene (A) 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 having projections fixed to a sheet , wherein the projections comprise a composition containing at least a high-crystalline polypropylene (A) and satisfy the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene (A) in the composition is from 40 to 95% by weight; (b) the projections 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 having a feed-side face and a permeate-side face ; wherein the separation membrane main body 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 , wherein the permeate-side channel member comprises a composition containing at least a high-crystalline polypropylene (A) and satisfies the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene (A) 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 (A) 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 having projections fixed to a sheet , wherein the projections comprise a composition containing at least a high-crystalline polypropylene (A) and satisfy the following requirements (a) and (b): (a) a content of the high-crystalline polypropylene (A) in the composition is from 40 to 95% by weight; (b) the projections 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 (A) in the composition is from 40 to 95% by weight; (b) the projections have a melting endothermic energy amount (ΔH), determined using a differential scanning calorimeter, of from 20 to 70 J/g. <EOS>