This paper examines the numeral expressions ``N(oun)+Nu(meral)+N(oun)``, ``Nu+N`` and ``N+Nu`` in the Oracle Bone inscriptions (OBI) of the Shang Dynasty and proposes that the ``N1+Nu+N2`` construction is directly related with the origin of classifiers in the Chinese linguistic history. The N1+Nu+N2 construction, comprised of two immediate constituents of subject N1 and predicate Nu and N2, is divided into two types: the case in which N1 is the same noun as N2, which is called a repeater and serves as a primitive classifier, and the case in which N1 is ａ different noun from N2, which has already lost its lexical meaning but retained its grammatical function as a typical classifier.