A method for producing a thin film multilayer substrate having a base substrate, and, which a plurality of conductor pattern layers superposed thereon through dielectric layers therebetween comprises the steps of: optically detecting the uppermost conductor pattern layer whenever the conductor pattern layer is formed on the base substrate; inspecting an absence and/or presence of a fault of the conductor pattern layer; and repairing a faulty portion in accordance with fault position data detected by the inspecting. According to this method, it is possible to enhance a production yield of relatively large size of thin film multilayer substrates which needs a relatively small amount of production at a high production cost, for mounting LSI chips thereon.