An aminoketone compound of the formula ##STR1## wherein ring A' means a five through eight-membered cyclic group which may be substituted and may contain one or two hetero atom(s) of O, S, N, as the ring-constituents; R.sup.1' means a hydrogen atom or a hydrocarbon residue which may be substituted; R.sup.2' means a hydrogen atom or a lower alkyl group; R.sup.3' means an aromatic group which may be substituted; R.sup.4' means a hydrogen atom, a lower alkyl group or aromatic group which may be substituted; n' means an integer of 2 to 7, or a salt thereof, is useful as an cholinesterase inhibitors and a cerebral function ameliorating agent.