PURPOSE: To obtain a filter, which has the high mechanical strength and can cope with high-density mounting, by forming a capacitor of a grounding electrode, a conductor and a dielectric substance, which are provided on an insulator substrate.

CONSTITUTION: On the surface of an insulator substrate 1, input/output electrodes 2 and 3, a grounding electrode 5, a dielectric substance 7 and a conductor 9 are provided. The input/output electrodes 2 and 3 and the grounding electrode 5 are formed so as to form the thick films by applying paste such as Ag, Ag-Pa or the like on the insulator substrate l with the means of screen printing, and drying the paste. The dielectric substance 7 is formed on the grounding electrode 5. The conductor 9, which electrically connects the input/ output electrodes 2 and 3, are formed on the dielectric substance 7. Thus, the thickness of the insulator substrate does not become the parameter, which determines capacitance. Therefore, the thickness of the insulator substrate can be made sufficiently thick, and the mechanical strength of the filter can be secured.