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 (51, 52, 53, 54, 55, 56) includes: a main substrate (513, 523, 533, 543, 553) made of a non-conductive material and having a first coupling structure (51a, 52a, 53a, 54c) and a second coupling structure (51c, 52c, 53c, 54a) 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 (513, 523, 533, 543, 553) 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 (51a, 52a, 53a, 54c, 55a, 56a) and the second coupling structure (51c, 52c, 53c, 54a, 55c, 56c) 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 (51, 52, 53, 54, 55, 56) includes: a main substrate (513, 523, 533, 543, 553) made of a non-conductive material and having a first coupling structure (51a, 52a, 53a, 54c) and a second coupling structure (51c, 52c, 53c, 54a) 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 (513, 523, 533, 543, 553) 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 (51a, 52a, 53a, 54c, 55a, 56a) and the second coupling structure (51c, 52c, 53c, 54a, 55c, 56c) form through-holes which are fitted into and mechanically coupled to supports of the at least two resonant elements (31 - 37). a main substrate (513, 523, 533, 543, 553) made of a non-conductive material and having a first coupling structure (51a, 52a, 53a, 54c) and a second coupling structure (51c, 52c, 53c, 54a) 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 (513, 523, 533, 543, 553) 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 (51a, 52a, 53a, 54c, 55a, 56a) and the second coupling structure (51c, 52c, 53c, 54a, 55c, 56c) form through-holes which are fitted into and mechanically coupled to supports of the at least two resonant elements (31 - 37).