PURPOSE: To prevent the fluctuation in waveforms in recording and reproducing by forming a magnetic metallic thin film of a structure having the columnar crystal structure nearly perpendicular to a surface facing a magnetic gap and specifying the ratio of the diameter to the length of the columnar crystals to ≤0.5.

CONSTITUTION: The structure of the magnetic metallic thin film 5 is formed of the columnar crystals which are continuous in a track width direction and the depth direction of the magnetic gap part 6 and are grown in the thickness direction of the film so as to form a uniformly graded layer. The ratio of the diameter to the length of the columnar crystals is substantially ≤0.5. The magnetic metallic thin film is formed nearly parallel with the magnetic gap surface over the entire part in the track width direction and the entire part in the depth direction of the magnetic gap part and is uniformly magnetized in the laminar state. The fluctuation in the waveforms in recording and reproducing is prevented in this way.