To facilitate stable recording and reproduction at a high density over a long period of time and improve a recording density to the extent beyond the level determined from the characteristics of a fixed magnetic head by improving running stability of a magnetic tape.

This apparatus is constituted by providing a fixed magnetic head 1 for performing recording and reproduction on one side of a magnetic tape T, and disposing a running stabilizing plate 2 for stabilizing running of the magnetic tape T so as to oppose the fixed magnetic head 1 with the magnetic tape T interposed therebetween, wherein the running stabilizing plate 2 is made of a soft magnetic material in order to increase a density of magnetic flux from the fixed magnetic head 1. Alternatively, the running stabilizing plate 2 is provided with an auxiliary head for increasing the magnetic flux density of the fixed magnetic head 1.