To provide a backing material capable of suppressing increase of a surface temperature of an ultrasonic probe.

This backing material is arranged on a back surface of at least one oscillator for transmitting and/or receiving ultrasonic waves in an ultrasonic probe. The backing material is provided with: a backing base material containing a polymer material; and a heat-conducting fiber arranged in the backing base material, having heat conductivity larger than that of the backing base material, and continuously penetrating the backing material from its first surface contacting at least one oscillator to its second surface different from the first surface.