The semiconductor memory device includes a memory cell array for storing a plurality of data on a word basis, a data input-output device and a read control device. The data input-output device includes a plurality of data holding circuits corresponding to one word. The data of one word is divided into a plurality of subwords. The read control device brings to an active state any one of a plurality of control signals corresponding to the plurality of subwords in response to an externally applied subword selection signal. The data holding circuit corresponding to one subword is thereby activated. As a result, any subword among the data of one word held in the data holding circuit is rewritten with a corresponding subword among the data of one word read from the memory cell array.