Microreactor for the desalination of a saline fluid, comprising at least one ion migration compartment, at least one ion separation compartment and at least one fluid collecting compartment: said ion migration compartment comprising: - at least one inlet opening for the saline fluid, - at least one main channel for the flow of saline fluid, - at least one first cathode electrode and at least one first anode electrode, - at least one first upper lateral channel for the evacuation of cations, substantially perpendicular to said main channel, - at least one second upper lateral channel for the evacuation of anions, substantially perpendicular to said main channel, said ion separation compartment comprising: - at least one left upper lip and at least one right upper lip projecting inside said main channel allowing collection of the ions, at least one second cathode electrode and at least one second anode electrode, - at least one first lateral channel for the evacuation of cations, substantially parallel to said main channel, - at least one second lateral channel for the evacuation of anions, substantially parallel to said main channel, - said main channel for the flow of saline fluid being positioned between the first lateral channel and the second lateral channel, - at least one first lower lateral channel for the evacuation of cations, substantially perpendicular to said main channel, - at least one second lower lateral channel for the evacuation of anions, substantially perpendicular to said main channel, said fluid collection compartment comprising: - at least one left lower lip and at least one right lower lip projecting inside the main channel, - at least one inner vessel collecting a non-saline fluid, - at least one external vessel collecting a highly saline fluid, characterised in that said first and second cathode electrodes (11A, 11B) and said first and second anode electrodes (12A, 12B) each respectively have a first surface (11F, 11G, 12F, 12G) in contact with the air and a second surface (11E, 11H, 12E, 12H) opposite said first surface, said second surface being in direct contact with a plastics wall (13B, 13C, 13A, 13D) which is in direct contact with the saline fluid. - at least one inlet opening for the saline fluid, - at least one main channel for the flow of saline fluid, - at least one first cathode electrode and at least one first anode electrode, - at least one first upper lateral channel for the evacuation of cations, substantially perpendicular to said main channel, - at least one second upper lateral channel for the evacuation of anions, substantially perpendicular to said main channel, - at least one left upper lip and at least one right upper lip projecting inside said main channel allowing collection of the ions, at least one second cathode electrode and at least one second anode electrode, - at least one first lateral channel for the evacuation of cations, substantially parallel to said main channel, - at least one second lateral channel for the evacuation of anions, substantially parallel to said main channel, - said main channel for the flow of saline fluid being positioned between the first lateral channel and the second lateral channel, - at least one first lower lateral channel for the evacuation of cations, substantially perpendicular to said main channel, - at least one second lower lateral channel for the evacuation of anions, substantially perpendicular to said main channel, - at least one left lower lip and at least one right lower lip projecting inside the main channel, - at least one inner vessel collecting a non-saline fluid, - at least one external vessel collecting a highly saline fluid,