Abstract: A matrix switching apparatus for preventing a pseudo input condition caused by a detour of a signal as well as output of an erroneous signal caused by a noise intruding into an apparatus and the like, in which a plurality of key lines having a plurality of switches are arranged in the first and second directions respectively. The apparatus includes a detector for detecting an ON condition of the plurality of the switches by a time-sharing detection, a counter for counting up a number of the switches which are in the ON condition simultaneously, both totally and respectively with the key lines, a storage means for storing a first, second, third and fourth statuses which represent the condition of the switches respectively, and a controller for inverting the second status into the first status.