To provide a method for manufacturing a metal matrix composite material by which even a large-size molded body can be perfectly impregnated all over with molten metal.

The method for manufacturing a metal matrix composite material in which particles or fibers of a material different from the metal of the metal matrix are dispersed through the metal matrix contains a step where a porous molded body composed of particles or fibers is immersed into molten metal and ultrasonic waves are applied by bringing an ultrasonic vibrator close to the molded body to impregnate the molded body with the molten metal. In this method, the application of ultrasonic waves is carried out while relatively moving the ultrasonic vibrator and the molded body in the above state where they are held in the close vicinity of each other. Although there are no particular limitations concerning the type of the relative movement, the relative movement can easily be performed by rotating at least either of the ultrasonic vibrator and the molded body.