The present invention provides a sealed nonaqueous electrolyte secondary battery which is equipped with a current interrupt device that is actuated by a rise in internal pressure of a battery case and in which the current interrupt device is actuated in a speedy and stable manner during an overcharge. In the sealed nonaqueous electrolyte secondary battery, an electrode body formed by a positive electrode 10 and a negative electrode that oppose each other via a separator, an electrolyte, and an overcharge inhibitor are housed in the battery case. The positive electrode 10 includes a positive electrode current collector 12 and a positive electrode active material layer 14 which is formed on the current collector and which mainly contains a positive electrode active material. In addition, a conductive material layer 16 which mainly contains a conductive material is formed between the positive electrode active material layer 14 and the separator. A porosity of the conductive material layer 16 is 35% or more and 55% or less.