A method of producing an organopolysiloxane compound in which a poly(N-acylalkyleneimine) segment comprising repeating units represented by formula (1): wherein R1 is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, an aralkyl group, or an aryl group, and n is 2 or 3, is bonded to a terminal end and/or a side chain of an organopolysiloxane segment, the method comprising: a step (a) of subjecting a cyclic imino ether compound represented by formula (I): wherein R1 is a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, an aralkyl group, or an aryl group, and n is 2 or 3, to ring opening polymerization in a solvent, thereby preparing a terminal reactive poly(N-acylalkyleneimine) solution; a step (b) of mixing a modified organopolysiloxane having an amino group at a terminal end and/or a side chain of its molecular chain and a solvent, thereby preparing a modified organopolysiloxane solution; a step (c) of mixing the terminal reactive poly(N-acylalkyleneimine) solution obtained in step (a) and the modified organopolysiloxane solution obtained in step (b), thereby allowing 65 to 95 mol % of total amino groups in the modified organopolysiloxane to react with the terminal reactive poly(N-acylalkyleneimine); and a step (d) of removing the solvent at 100 to 200° C. after completing step (c).