The present invention relates to a method for producing free radical water. The method for producing free radical water of the present invention is a method for producing free radical water containing hydrogen radicals and/or hydroxyl radicals, and it includes the steps of: electrolyzing water to obtain hydrogen water； electrolyzing water to obtain hydrogen The step of increasing the oxygen ion concentration of the hydroxide ion water before electrolysis； the step of mixing the above-mentioned hydrogen water and the above-mentioned hydroxide ion water； and the step of applying ultrasonic waves to the mixed water.本發明係關於一種自由基水之製造方法。本發明之自由基水之製造方法係含有氫自由基及/或羥基自由基之自由基水之製造方法，且其包括：對水進行電解而獲得氫水之步驟；對水進行電解而獲得氫氧離子濃度較電解前增加之氫氧離子水之步驟；將上述氫水與上述氫氧離子水進行混合之步驟；及對所混合之混合水施加超音波之步驟。
