A rubber composition for a hollow ball includes a base rubber and an inorganic filler. A weight reduction rate TGA650 from room temperature to 650° C. and a weight reduction rate TGA850 from room temperature to 850° C. of the rubber composition are measured under an air atmosphere by thermogravimetry conforming to JIS K0129. The weight reduction rate TGA650 of the rubber composition is not less than 63% and not greater than 99%. A difference (TGA850−TGA650) between the weight reduction rates TGA850 and TGA650 of the rubber composition is not less than 0% and not greater than 7%. A hollow ball 2 includes a hollow core 4 formed from the rubber composition.