A reconfigurable operation apparatus includes a reconfigurable circuit, a storage unit and a control unit. The reconfigurable circuit has a plurality of small circuits and reconfigures a circuit using the small circuit selected from the plurality of small circuits based on recorded circuit information. The storage unit stores first and second circuit information which corresponds to first and second compression circuits, respectively. The control unit reconfigures the reconfigurable circuit into the first or second compression circuit by recording the first or second circuit information in the reconfigurable circuit in accordance with an input data string.