Abstract: A variable logic operation apparatus which receives n-nary input data, logic function setting data and connection data, and performs logic operations on the input data based on a logic expression. The apparatus includes a plurality of logic operation units, each logic operation unit selecting a respective logic operation from a group of at least one logic operation, and outputting a single result based on the selected logic operation. The selected logic operation is selected by the logic function setting data. A plurality of connection devices connect the plurality of logic operation units in accordance with the connection data to form a tree structure. The tree structure is changeable by changing the connection data. Thus, the logic expression is converted into the tree structure in accordance with the setting data and the connection data.