A semiconductor memory apparatus capable of detecting an error in data input/output includes a memory cell block including a plurality of memory cells. A data input unit receives data from outside the semiconductor memory apparatus and performs predetermined signal processing to record the received data in the memory cell block. A first global data line is connected between the data input unit and the memory cell block. A data output unit receives data from the memory cell block and performs predetermined signal processing to output the received data to the outside of the semiconductor memory apparatus. A second global data line is connected between the memory cell block and the data output unit. A multiplexer selectively outputs data from the first or second global data line in response to a control signal. An error detection code generator generates an error detection code having a plurality of bits to detect whether the data output from the multiplexer includes an error, and outputs the error detection code to the outside of the semiconductor memory apparatus.