To provide a crushing and volume reduction treatment method of an asbestos-containing building material capable of crushing and volumetrically reducing the asbestos-containing building material without scattering asbestos, and an apparatus therefor.

A crushing means 3 for crushing a slate S being the asbestos-containing building material is provided in a casing 2 and dust-proof water W is stored in the casing 2 so that at least the crushing means 3 is immersed in the dust-proof water W. Then, the slate S is charged in the casing 2 and the asbestos-containing building material is crushed by the crushing means 3 while immersed in the dust-proof water W.