To provide an on-vehicle brushless motor device capable of being downsized with respect to an axial direction of a rotor and a method of manufacturing the same. The on-vehicle brushless motor device 1 includes a brushless motor 10 and an electronic substrate 30. The brushless motor 10 includes a rotor 12 and a stator 16 including a plurality of coils 18 arranged around the rotor 12. The electronic substrate 30 includes a through hole 34 penetrating in the axial direction X of the rotor 12 and includes a substrate body 32 arranged along a plane P intersecting the axial direction X on the side opposite to the output shaft of the brushless motor 10, and a terminal 40 fixed on the surface of the substrate body 32 on the side opposite to the rotor 12. A coil wire 20 of the coil 18 is inserted into the through hole 34 and is welded to the terminal 40 on the opposite side of the rotor 12 with respect to the substrate body 32.