The study of both the magnetization distribution of recorded and non-recorded media is needed if magnetic recording densities are to be increased. There are various magnetic recording media depending on the type of recording drive such as hard disc drive, tape drive, magneto-optical disc drive, etc. The magnetization of the recorded bits of each medium has its own direction, i.e., parallel, oblique, or perpendicular to the medium plane. Thus, spin-SEM is advantageous to the study of these recording media, since it can detect the three components of the magnetization vector with a spatial resolution of several nanometers. In this chapter, I review how the spin-SEM contributes to increasing the recording density of various recording media.