A cavity type wireless frequency filter having a cross-coupling notch structure, the filter comprising: a housing having a hollow therein to provide a plurality of cavities and an open surface at one side of the housing ; a cover for blocking the open surface of the housing ; a plurality of resonant elements (31 - 37) disposed in the hollow of the housing ; and a notch substrate installed for cross-coupling between at least two resonant elements (31 - 37) among the plurality of resonant elements (31 - 37) to provide a stable notch characteristic, wherein a notch is an attenuation pole used to improve the skirt characteristic of the filter, wherein the notch substrate includes: a main substrate made of a non-conductive material and having a first coupling structure and a second coupling structure which are mechanically coupled to the at least two resonant elements (31 - 37); and a conductive line (511, 512, 521, 522, 531, 532, 541, 542, 551, 561-564) implemented with a conductor pattern formed on the main substrate and transmitting a signal of a first resonant element (31 - 37) among the at least two resonant elements (31 - 37) to a second resonant element (31 - 37) thereamong through a non-contact coupling method, wherein the first coupling structure and the second coupling structure form through-holes which are fitted into and mechanically coupled to supports of the at least two resonant elements (31 - 37). a housing having a hollow therein to provide a plurality of cavities and an open surface at one side of the housing ; a cover for blocking the open surface of the housing ; a plurality of resonant elements (31 - 37) disposed in the hollow of the housing ; and a notch substrate installed for cross-coupling between at least two resonant elements (31 - 37) among the plurality of resonant elements (31 - 37) to provide a stable notch characteristic, wherein a notch is an attenuation pole used to improve the skirt characteristic of the filter, wherein the notch substrate includes: a main substrate made of a non-conductive material and having a first coupling structure and a second coupling structure which are mechanically coupled to the at least two resonant elements (31 - 37); and a conductive line (511, 512, 521, 522, 531, 532, 541, 542, 551, 561-564) implemented with a conductor pattern formed on the main substrate and transmitting a signal of a first resonant element (31 - 37) among the at least two resonant elements (31 - 37) to a second resonant element (31 - 37) thereamong through a non-contact coupling method, wherein the first coupling structure and the second coupling structure form through-holes which are fitted into and mechanically coupled to supports of the at least two resonant elements (31 - 37). a main substrate made of a non-conductive material and having a first coupling structure and a second coupling structure which are mechanically coupled to the at least two resonant elements (31 - 37); and a conductive line (511, 512, 521, 522, 531, 532, 541, 542, 551, 561-564) implemented with a conductor pattern formed on the main substrate and transmitting a signal of a first resonant element (31 - 37) among the at least two resonant elements (31 - 37) to a second resonant element (31 - 37) thereamong through a non-contact coupling method, wherein the first coupling structure and the second coupling structure form through-holes which are fitted into and mechanically coupled to supports of the at least two resonant elements (31 - 37). <EOS>