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PROBLEM TO BE SOLVED : To provide a silicon-based ceramic negative ion generation material which improves the human natural healing potentiality by emanating a low dose of radiation and a material for the footwear, especially a midsole and a production method thereof. SOLUTION : A low radioactive negative ion generation material is mainly composed of silicon-based ceramics, which contains a mineral containing a radioactive rare earth element of 10-30% by mass and the material for the footwear holding it.