PURPOSE: To combine short stubs for coarse adjustment and for fine adjustment and to widen the variable adjustment range of frequency adjustment by arranging a second ground conductor film to which only a part of the short stub is placed oppositely inside a dielectric member.

CONSTITUTION: On both sides of one end of a microstrip line 1, a first short stub 11 and a second short stub 12 are respectively formed. The dielectric member 2 of this resonance circuit board 10 is composed of at least two dielectric layers 21 and 22 and the second ground conductor film 31 is interposed in a part between the layers. The second ground conductor film 31 is formed only at a position corresponding to the second short stub 12 and is arranged so as not to be placed oppositely at least to the first short stub 11. For instance, the coarse adjustment is made possible by cutting off the short stub opposite to a ground conductor film 3 and the fine adjustment is made possible by cutting off the short stub opposite to the second ground conductor film 31.