To suppress tampering of unique information recorded on a recording medium.

In this invention, when servo information is recorded in the servo zone of a magnetic disk, a recording pattern 151 consisting of a magnetization transition point a1 and a magnetization transition point b1 is recorded in the prescribed area of a data zone and a recording pattern 152 consisting of a magnetization transition point a2 and a magnetization transition point b2 is recorded with a recording current weaker than that of ID information so that its phase does not overlap with the magnetization transition point a1 and the magnetization transition point b1 in the same area as the area where the recording pattern 151 is recorded in the next circulation. The area where the recording patterns 151, 152 are recorded is reproduced as a reproduced signal waveform 161 in which amplitude of a point A2 and a point B2 to which the magnetization points a2, b2 are made to correspond is large and amplitude of a point A1 and a point B1 to which the magnetization points a1, b1 are made to correspond is small. The invention is applicable to a recording and reproducing device for recording, viewing and listening contents which need protection of intellectual property.