An organic polysilane, which can produce signals respectively derived from a Si—O bond, an alkoxy group and a hydroxy group at levels equal to or lower than the detection limits in 29Si and 13C CP/MAS NMR analysis, can be produced by a method which includes: polymerizing an organic dihalosilane in an aprotic solvent in the presence of an alkali metal and/or an alkali earth metal to produce a mixture containing an organic polysilane having a terminal halogeno group; adding a solution containing an organic lithium compound and an aprotic polar solvent to the mixture to inactivate the organic polysilane having the terminal halogeno group; and then adding a protic polar solvent to the resultant mixture to deactivate the alkali metal and/or the alkali earth metal.