In the process for producing a laminated substrate (1) such as electronic substrates (2; 3), when applying a sealing agent (7) to the end face of substrates (2; 3) combined together to seal it, first the sealing agent (7) is applied to a target area in the form of successive beads (7), and then a stream of compressed gas (10) is blown against the successive beads (7) from a gas ejecting nozzle (9) so as to scan the successive beads (7). The method can effectively fill the indentation or the stepped area formed along the end face with the sealing agent (7).