A motor being a brushless motor driven by an inverter which uses pulse width modulation, comprising: a stator including a stator iron-core having a winding wound thereon, wherein the stator iron-core is molded with a mold material; a rotor including a rotary body confronting the stator, and one shaft joined to the rotary body such that it extends through the rotary body at the center; two bearings (15, 15a, 15b) having a plurality of iron balls, an outer ring and an inner ring for supporting the shaft; two conductive brackets (17, 19) fixing the two bearings (15a, 15b), each of the two bearings (15a, 15b) being fixed with one of the brackets (17, 19) and the outer ring of each of the two bearings (15a, 15b) being electrically connected to the one of the two brackets (17, 19); and a printed circuit board having a drive circuit mounted thereon for driving the winding; characterized in that: the rotary body is provided with a dielectric layer made of insulating resin between a radial outer rim of the rotary body and the shaft, wherein the rotary body is formed of a permanent magnet along a circumferential direction at the outmost periphery of the rotary body, an outer iron-core (31 a) forming an outer periphery of a rotor iron core, the dielectric layer, and an inner iron-core forming an inner periphery of the rotor iron-core, wherein the outer iron-core, the dielectric layer and the inner iron-core are placed in this order from a radial outer rim of the rotary body radially inwards to the shaft; the two brackets (17, 19) are electrically connected together, an impedance adjusting member, being at least one of a capacitor and a resistance element,is connected between the stator iron-core and either one of the brackets (17, 19) for adjusting electrical impedance at the high frequency signal due to the pulse width modulation so that an electrical impedance between the stator iron core and the outer ring of one of the bearings is matched to an electrical impedance between the stator iron core and the inner ring of the same one of the bearings. a stator including a stator iron-core having a winding wound thereon, wherein the stator iron-core is molded with a mold material; a rotor including a rotary body confronting the stator, and one shaft joined to the rotary body such that it extends through the rotary body at the center; two bearings (15, 15a, 15b) having a plurality of iron balls, an outer ring and an inner ring for supporting the shaft; two conductive brackets (17, 19) fixing the two bearings (15a, 15b), each of the two bearings (15a, 15b) being fixed with one of the brackets (17, 19) and the outer ring of each of the two bearings (15a, 15b) being electrically connected to the one of the two brackets (17, 19); and a printed circuit board having a drive circuit mounted thereon for driving the winding; two bearings (15, 15a, 15b) having a plurality of iron balls, an outer ring and an inner ring for supporting the shaft; two conductive brackets (17, 19) fixing the two bearings (15a, 15b), each of the two bearings (15a, 15b) being fixed with one of the brackets (17, 19) and the outer ring of each of the two bearings (15a, 15b) being electrically connected to the one of the two brackets (17, 19); and a printed circuit board having a drive circuit mounted thereon for driving the winding; characterized in that: the rotary body is provided with a dielectric layer made of insulating resin between a radial outer rim of the rotary body and the shaft, wherein the rotary body is formed of a permanent magnet along a circumferential direction at the outmost periphery of the rotary body, an outer iron-core (31 a) forming an outer periphery of a rotor iron core, the dielectric layer, and an inner iron-core forming an inner periphery of the rotor iron-core, wherein the outer iron-core, the dielectric layer and the inner iron-core are placed in this order from a radial outer rim of the rotary body radially inwards to the shaft; the two brackets (17, 19) are electrically connected together, an impedance adjusting member, being at least one of a capacitor and a resistance element,is connected between the stator iron-core and either one of the brackets (17, 19) for adjusting electrical impedance at the high frequency signal due to the pulse width modulation so that an electrical impedance between the stator iron core and the outer ring of one of the bearings is matched to an electrical impedance between the stator iron core and the inner ring of the same one of the bearings. the rotary body is provided with a dielectric layer made of insulating resin between a radial outer rim of the rotary body and the shaft, wherein the rotary body is formed of a permanent magnet along a circumferential direction at the outmost periphery of the rotary body, an outer iron-core (31 a) forming an outer periphery of a rotor iron core, the dielectric layer, and an inner iron-core forming an inner periphery of the rotor iron-core, wherein the outer iron-core, the dielectric layer and the inner iron-core are placed in this order from a radial outer rim of the rotary body radially inwards to the shaft; the two brackets (17, 19) are electrically connected together, an impedance adjusting member, being at least one of a capacitor and a resistance element,is connected between the stator iron-core and either one of the brackets (17, 19) for adjusting electrical impedance at the high frequency signal due to the pulse width modulation so that an electrical impedance between the stator iron core and the outer ring of one of the bearings is matched to an electrical impedance between the stator iron core and the inner ring of the same one of the bearings.