A semiconductor memory device includes a memory cell array from which all bits of a data signal having a first number of the bits composed of a main data signal and an error detection/correction code data signal are simultaneously read, a sense amplifier for amplifying the read data signal, a selection unit for selecting a data signal having a second number of bits forming a part of the data signal amplified by the sense amplifier, and an error detection/correction unit for performing error detection and correction based on at least a part of the selected data signal having the second number of bits, wherein the selection by the selection unit is performed based on a row address.