A semiconductor memory apparatus includes a first comparison block configured to compare a plurality of channel data with one another and generate a first comparison signal, or output one of the plurality of channel data as the first comparison signal, in response to a plurality of channel select signals; a second comparison block configured to compare the plurality of channel data and generate a second comparison signal when the plurality of channel select signals have a predetermined combination and a channel detection signal has a predetermined logic level; a channel selection detection block configured to enable the channel detection signal when only one channel select signal among the plurality of channel select signals is enabled; and a combined output block configured to enable a test result signal when at least one comparison signal of the first and second comparison signals is enabled.