To facilitate bonding of articles at a low temperature without degrading electrical contact between the articles. An oxide film reducing treatment with hydrogen radicals is carried out for surfaces of lead-out electrodes (5) and bump electrodes (6) on the lead-out electrodes (5) of a semiconductor chip (2) and surfaces of lead-out electrodes (8) of an intermediate substrate (3), and, after that, the bump electrodes (6) of the semiconductor chip (2) and the lead-out electrodes (8) of the intermediate substrate (3) are aligned with each other. After that, a pressure is applied to bond the bump electrodes (6) and the lead-out electrodes (8).