A concentration of the polycyclic aromatic compound in the solution B is preferably between from 10^?2 mol/L to 5 mol/L, and particularly preferably between from 10^?2 mol/L to 3 mol/L. When the concentration of the polycyclic aromatic compound is not smaller than 10^?2 mol/L, a reaction between the lithium metal and the polycyclic aromatic compound tends to proceed, and a reaction time may be shortened. When the concentration of the polycyclic aromatic compound is not larger than 5 mol/L, a reaction product between the polycyclic aromatic compound and the lithium metal is difficult to attach to the silicon compound, and the silicon compound powder may be readily separated. Further, when the negative electrode active material is formed into the non-aqueous electrolyte secondary battery, a reaction residue is not eluted into the electrolytic solution, and the battery characteristics may be suppressed from deteriorating due to a side reaction.

Further, a time during which the solution B and the silicon compound are contacted is preferably set to 3 minutes or longer and 100 hours or shorter. When the contact time is not shorter than 3 minutes, a sufficient drawing amount of the lithium may be obtained. Further, at the time point when the contact time becomes 100 hours, the lithium desorption into the solution B from the silicon compound reaches a substantial equilibrium state. Further, the reaction temperature is preferable to be from ?20° to 200° C., and more preferable to be from 0° C. to 50° C. Particularly, the reaction temperature is preferably set in the neighborhood of 20° C. In the temperature range as was described above, since a reaction speed is difficult to decrease, and the lithium compound is difficult to generate precipitate due to a side reaction, a desorption rate of the lithium from the silicon compound is improved.