A semiconductor memory apparatus includes a first data selection section inputted with the first data and second data and output one of the first data and the second data as first selection data in response to an address signal, a second data selection section inputted with the second data and the first selection data and output one of the second data and the first selection data as second selection data depending upon an input and output mode, and a data output section configured to be inputted with the first and second selection data and output first and second output data.