Abstract: In a method and device for fastening an electronic circuit substrate onto a support, a looped line of an adhesive product in the viscous state is deposited on one of the surfaces of the substrate or the support to be fastened to one another. The surfaces are placed opposite each other in order to establish a space defined by the line of adhesive product and areas of the opposing surfaces inside the line. A reduced pressure is applied to the space by a suction device so as to squash the line of adhesive product between the two surfaces to be assembled, in order to spread the viscous adhesive product in a layer with a uniform thickness, and the layer formed in this way is dried. The method and device are applied to the fastening of electronic circuit substrates in protective casings.