Summary: We consider a realization of the functions of a three-valued logic by the circuits with unreliable functional gates in a full finite basis. It is assumed that gates turn in faulty condition independently and the faults can be arbitrary (e.g., inverse or constant). We describe a class \(G\) of the functions of a three-valued logic whose circuits can be used to improve the reliability of initial circuits. With inverse faults on the outputs of the basic gates, using functions of the class \(G\) constructively, we prove that a function different from any variable can be realized with a reliable circuit (we remind that a function equal to a variable can be realized reliably without using functional elements). In particular, if the basis contains at least one function from \(G\), then the proposed circuits are not only reliable, but asymptotically reliability optimal for all functions different from any variable.