A multilayer circuit board including a plurality of conductor layers and a plurality of resin insulation layers which are laminated alternately, comprising: a first wiring (31, 33) formed on a first layer of the plurality of conductor layers; a second wiring (21, 22) formed on a second layer of the plurality of conductor layers; and a third wiring formed on a third layer of the plurality of conductor layers, wherein portions of the first wiring (31, 33) and the second wiring (21, 22) which face each other in a laminated direction in which the plurality of conductor layers are laminated extend in parallel; wherein the first wiring (31, 33) and the second wiring (21, 22) are arranged so as to weaken a magnetic field generated by a current which flows through the first wiring (31, 33) and a magnetic field generated by a current which flows through the second wiring (21, 22) to each other; wherein the first wiring (31, 33) and the second wiring (21, 22) comprise a power source wiring and a ground wiring in which currents flow therethrough in an opposite direction to each other; and wherein the first wiring (31, 33), the second wiring (21, 22) and the third wiring comprise wirings which are respectively connectable to phases of a multiphase motor provided outside via a U-phase wiring, a V-phase wiring and a W-phase wiring; wherein an FET (15u, 15v, 15w, 16u, 16v, 16w), a ground terminal and a power source terminal are provided on the third layer; wherein the ground wiring formed on the second layer is connected to the ground terminal via a through hole of the third layer; wherein the power source wiring formed on the first layer is connected to the power source terminal via a through hole of the second layer; wherein the U-phase wiring, the V-phase wiring and the W-phase wiring have layer shapes, and are provided on the first layer, the second layer and the third layer, respectively; and wherein portions of respective different phase wirings of the U-phase wiring, the V-phase wiring and the W-phase wiring are superposed in the laminated direction of the plurality of the conductor layers. a first wiring (31, 33) formed on a first layer of the plurality of conductor layers; a second wiring (21, 22) formed on a second layer of the plurality of conductor layers; and a third wiring formed on a third layer of the plurality of conductor layers, wherein portions of the first wiring (31, 33) and the second wiring (21, 22) which face each other in a laminated direction in which the plurality of conductor layers are laminated extend in parallel; wherein the first wiring (31, 33) and the second wiring (21, 22) are arranged so as to weaken a magnetic field generated by a current which flows through the first wiring (31, 33) and a magnetic field generated by a current which flows through the second wiring (21, 22) to each other; wherein the first wiring (31, 33) and the second wiring (21, 22) comprise a power source wiring and a ground wiring in which currents flow therethrough in an opposite direction to each other; and wherein the first wiring (31, 33), the second wiring (21, 22) and the third wiring comprise wirings which are respectively connectable to phases of a multiphase motor provided outside via a U-phase wiring, a V-phase wiring and a W-phase wiring; wherein an FET (15u, 15v, 15w, 16u, 16v, 16w), a ground terminal and a power source terminal are provided on the third layer; wherein the ground wiring formed on the second layer is connected to the ground terminal via a through hole of the third layer; wherein the power source wiring formed on the first layer is connected to the power source terminal via a through hole of the second layer; wherein the U-phase wiring, the V-phase wiring and the W-phase wiring have layer shapes, and are provided on the first layer, the second layer and the third layer, respectively; and wherein portions of respective different phase wirings of the U-phase wiring, the V-phase wiring and the W-phase wiring are superposed in the laminated direction of the plurality of the conductor layers.