To improve smoothness, durability and traveling property in a rear layer of a magnetic recording medium.

A polymer graft carbon black obtained by condensation reaction of a carbon black having ≥0.1mequiv./g quinone with an urethane based polymer having an amino group is incorporated in the coating material for the rear layer for the magnetic recording medium having a magnetic layer and the rear layer respectively on the surfaces opposed to each other in a supporting body incorporates. And the number average molecular weight of the urethane based polymer having the amino group is controlled to 1000-50000.