PURPOSE: To readily and efficiently remove trace amounts of halogenated organic compound which are impurities and obtain the titled high-purity compound, by bringing an organosilicon compound containing impurities into contact with an organolithium compound.

CONSTITUTION: An organosilicon compound (example; organosilanes such as diemthyldichlorosilane or organosiloxanes such as hexamethyldisiloxane) containing a halogenated organic compound such as methyl chloride, chlorobenzene and biphenyl chloride as an impurity is brought into contact with an organolithium compound (example; methyl lithium, etc.) while stirring, preferably at ≤50°C and then the organosilicon compound is separated to afford the aimed compound.