A normal-insulator-superconductor microrefrigerator in which a superconducting single crystal is both the substrate and the superconducting electrode of the NIS junction. In the electrooptic device, at least one dielectric layer of the plurality of dielectric layers is formed so as not to overlap with a sealing region on the first substrate, on which the sealing member is arranged. At least a portion of the horizontal wall is removed to expose the photoresist film pattern remaining within the converted oxide layer.