A multilayer wiring board mounted with a magnetic antenna for transmitting and receiving a magnetic field component, characterized in that the magnetic antenna is produced by a method comprising: providing a single- or multi-layered magnetic layer comprising a square or rectangular molded sheet or sheets of a mixture of a magnetic powder and a binder resin; forming through-holes in said magnetic layer; filling said through-holes with an electrode material; forming an electrode layer of an electrode material on each of outer surfaces of said magnetic layer perpendicular to said through-holes such that said electrode layers are connected to said through-holes to form coils and that opposite ends of said magnetic layer conform to open ends of a magnetic circuit; forming an insulating layer on each of both outer surfaces of said coils having the electrode layers; forming a conductive layer on an outer surface of at least one of said insulating layers to obtain a laminate; cutting the laminate along lines passing said through-holes and along lines corresponding to said open ends of said coils; and calcining the cut laminate into a unitary body, wherein: the magnetic antenna further comprises an additional magnetic layer provided on an outer surface of said conductive layer provided on said insulating layers; or the magnetic antenna further comprises an additional insulating layer provided on an outer surface of said conductive layer provided on said insulating layers, and an additional magnetic layer provided on an outer surface of said additional insulating layer; and characterized in that the or each magnetic layer comprises a Ni-Zn based ferrite magnetic material produced by calcination in which the ferrite powder has a composition of 45 to 49.5 mol% of Fe 2 O 3, 9.0 to 45.0 mol% of NiO, 0.5 to 35.0 mol% of ZnO and 4.5 to 15.0 mol% of CuO; and the or each insulating layer comprises a Zn based ferrite powder having such a composition that a sintered body formed therefrom has a volume resistivity of 10 8 Ohm.cm or higher, or a glass based ceramic. providing a single- or multi-layered magnetic layer comprising a square or rectangular molded sheet or sheets of a mixture of a magnetic powder and a binder resin; forming through-holes in said magnetic layer; filling said through-holes with an electrode material; forming an electrode layer of an electrode material on each of outer surfaces of said magnetic layer perpendicular to said through-holes such that said electrode layers are connected to said through-holes to form coils and that opposite ends of said magnetic layer conform to open ends of a magnetic circuit; forming an insulating layer on each of both outer surfaces of said coils having the electrode layers; forming a conductive layer on an outer surface of at least one of said insulating layers to obtain a laminate; cutting the laminate along lines passing said through-holes and along lines corresponding to said open ends of said coils; and calcining the cut laminate into a unitary body, wherein: the magnetic antenna further comprises an additional magnetic layer provided on an outer surface of said conductive layer provided on said insulating layers; or the magnetic antenna further comprises an additional magnetic layer provided on an outer surface of said conductive layer provided on said insulating layers; or the magnetic antenna further comprises an additional insulating layer provided on an outer surface of said conductive layer provided on said insulating layers, and an additional magnetic layer provided on an outer surface of said additional insulating layer; and characterized in that the or each magnetic layer comprises a Ni-Zn based ferrite magnetic material produced by calcination in which the ferrite powder has a composition of 45 to 49.5 mol% of Fe 2 O 3, 9.0 to 45.0 mol% of NiO, 0.5 to 35.0 mol% of ZnO and 4.5 to 15.0 mol% of CuO; and the or each insulating layer comprises a Zn based ferrite powder having such a composition that a sintered body formed therefrom has a volume resistivity of 10 8 Ohm.cm or higher, or a glass based ceramic.