OVERCURRENT BREAKING DEVICE

PURPOSE:To enable the simple and compact constitution of a device by providing a contact part and superconductor part at a conductor passage, and a working body comprising a permanent magnet on the superconductor part. CONSTITUTION:In the condition where the density of a current flowing through a conductor passage does not exceed the critical current density of a superconductor part 5, a working body 7 comes to be afloat due to the Meissner effect of the superconductor part 5, and a current is thereby made to flow through the conductor passage with the contact part 4 thereof kept connected. On the other hand, when an overcurrent flows in the conductor passage and the density thereof exceeds the critical current density of the superconductor part 5, the Meissner effect of the superconductor part 5 disappears and the the working body 7 is positioned on the superconductor part 5 without being afloat, thereby making the contact part 4 disconnected and interrupting the overcurrent. According to the aforesaid construction, a breaking device can be made compact with simple constitution.