A weak-magnetic field sensor using printed circuit board manufacturing technique and a method of manufacturing the same which detects earth magnetism to obtain positional information is disclosed. The sensor comprises a magnetic layer patterned in a certain shape; a first stacked board stacked on a lower surface of the magnetic layer and formed with a first driving pattern; a second stacked board stacked on an upper surface of the magnetic layer and formed with a second driving pattern, the first and second driving patterns being electrically connected to each other; a third lower stacked board stacked on a lower surface of the first stacked board and formed with a first pickup pattern; and a third upper stacked board stacked on an upper surface of the second stacked board and formed with a second pickup pattern, the third lower and upper stacked boards being electrically connected to each other.