To improve positional accuracy of components, and to restrict lowering of the characteristics of an electronic component.

Two or more components are relatively positioned, and after the components in the positioned state have been unified as an element assembly by a bonding means, the element assembly is fixed inside a case. The bonding means is solder. One of components is a ferrite assembly having a ferrite core and a strip line, and an electronic component is a non-reciprocal circuit element. A positioning jig, having a positioning part corresponding to the ferrite assembly or to a component other than the ferrite assembly, is used. In a state, in which one of the ferrite assembly or a component other than the ferrite assembly is put in the positioning part, the positioning is carried out by piling the other component.