To provide a method of utilizing a neutralized filtrate of a treating solution for making asbestos harmless which reduces the costs for treating waste water of the neutralized filtrate of a treating solution for making asbestos-containing waste harmless and allows reuse of the neutralized filtrate in a treatment of making an asbestos-containing waste harmless and as a raw material for cement.

The method of utilizing a neutralized filtrate of a treating solution for making asbestos harmless includes: treating asbestos-containing waste with a treating solution containing hydrochloric acid and a fluorine-containing compound to make asbestos in the waste harmless; neutralizing the treating solution by adding slaked lime to the treated waste solution; filtrating the resultant precipitation to obtain a neutralized filtrate; adding sulfuric acid to the neutralized filtrate and filtering; and reusing the resultant solid content as a raw material for cement and the resultant filtrate as a treating solution for making asbestos-containing waste harmless.