A negative electrode active material for nonaqueous secondary batteries is disclosed. The active material contains a silicon solid solution having one or more than one of a group 3 semimetal or metal element, a group 4 semimetal or metal element except silicon, and a group 5 nonmetal or semimetal element incorporated in silicon as a solute element. The solute element is present more on the crystal grain boundaries of the silicon solid solution than inside the grains.