PURPOSE: To obtain a Josephson junction device which can be enhanced in Rn by a method wherein a substrate is provided with steps which are arranged adjacent to each other.

CONSTITUTION: A Josephson junction device is primarily composed of an SrTiO3 (100) substrate 1 on which stepped level differences 11 to 13 are provided and a Y1Ba2Cu3O7-x oxide superconductive thin film 2 formed thereon, wherein the oxide superconductive thin film 2 is composed of two superconductive electrodes 21 and 22 and a narrow bridge 3 which connects the electrodes 21 and 22 together. The oxide superconductive thin film 2 deposited on the vertical surfaces of the 11 to 13 is different in crystal orientation from that deposited on the horizontal surface of the substrate 1, so that grain boundaries 31 to 36 are produced in the film 2 on the level difference 11 to 13 to constitute a Josephson junction of weak link. Therefore, Josephson junctions are arranged in series to act substantially as a single Josephson junction, so that a Josephson junctions device of this constitution can be enhanced in Rn and output voltage when it is applied to a sensor.