An optical pickup unit, an apparatus for recording/reproducing data, a control method, and a recording medium are disclosed. Each of the optical pickup unit and the recording/reproducing apparatus includes a near-field lens, and uses a high-refraction lens, conically shaped, to effectively use the near-field. Two lens units are required to be compatible with a conventional recording medium. The lens unit is designed in consideration of a distance between the recording medium and the lens, and the tilt or vibration of the lens units is controlled.