PURPOSE: To obtain a thin hybrid integrated circuit product by providing a multilayer circuit substrate with a recessed part and housing the surface mounting electronic parts such as a semiconductor inside the recessed part turning inside and out for being circuitlike connected.

CONSTITUTION: A recessed part 12 having a size corresponding to the outline of the surface mounting electronic parts 2 is formed in the central part of a substrate 11. This recessed part 12 is formed in the form where a package 3 of the surface mounting electronic parts 2 can be housed in its inside and when the surface mounting electronic parts 2 are housed in the recessed part 12 turning inside out, electrodes 4 outwardly projected from the package 3 can be brought in contact with the surface of the substrate 11 around the recessed part 12. Accordingly, the surface mounting electronic parts 2 can be mounted on the substrate 11 in a state where almost the whole of the package 3 is housed inside the recessed part. Thereby, a hybrid integrated circuit can be made in a thin type.