To provide a ball washing machine capable of washing balls cleanly without taking labor and time.

The machine is provided with a rotary drum 1 to be rotated, a shaft 2 provided on the rotary shaft core L of the drum 1 and rotated integrally with the drum 1, and elastic grinding members 3 provided on the shaft 2 in the form of extending in a radial direction. A distance from the tip part of the grinding members 3 to the inner face of the drum 1 is set to be 30% to 90% of the diameter of a ball B, and the surface of the ball B which is soaked at least partially in a washing liquid F in the drum 1 is rubbed to be washed by the grinding members 3 with the rotation of the drum 1.