A magneto-resistive head, a magnetic tape and a magnetic tape recording/reproducing system, which are capable of suppressing the formation of protrusions around a magneto-resistive element, thereby preventing the occurrence of such problems as spacing loss and tape damage, are provided. A thermally conductive member that is connected to the magneto-resistive element is formed of a material having a thermal conductivity greater than 20 W/mK so as to efficiently release the heat generated when the magneto-resistive element is in use and suppress the rise in temperature around the magneto-resistive element. In addition, by selecting, for a lubricant layer formed on the surface of the magnetic tape, a material whose melting point is higher than the operating temperature of the magneto-resistive element, the lubricant layer is prevented from melting even when the magneto-resistive element is in use and when the temperature of the magnetic head thus rises.