PURPOSE: To obtain a small-sized circuit and to prevent malfunction due to a magnetic flux trap by forming the circuit only by a resistor and Josephson junction.

CONSTITUTION: A Josephson (J) junction 21 and a resistor 26 are connected to a gate current supplying line 32 in parallel, a J circuit 24 is connected to the J junction 21 in series and a data input line 34 is connected to the input terminal of the J circuit 24. A J circuit 25, a resistor 28 and a J junction 22 are connected to a gate current supplying line 33 in series and a data output line 35 and a J junction 23 are connected to the output terminal of the J circuit 25 in parallel through a resist 29. A data output line 36 is connected to a connection point between the resistor 28 and the J junction 22 and the output terminal of the J circuit 24 is connected to the J circuit 25 through a resistor 27. Since the titled circuit is formed only by the resistor and Josephson junction the circuit reduces the size and the malfunction due to the magnetic flux trap is prevented.