BATTERY MANUFACTURING METHOD, AND NUT FASTENING DEVICE

PROBLEM TO BE SOLVED: To provide a battery manufacturing method and a nut fastening device capable of detecting mixture of foreign materials into fastened spots and carrying out fastening.SOLUTION: A nut runner 200 fastens a bolt 1 (bolts 171, 181) and a nut 2 while measuring contact resistance between a fastened member 3 (bus bar 190) and a fastened member 4 (positive electrode terminal 172, negative electrode terminal 182). The contact resistance between the fastened member 3 (bus bar 190) and the fastened member 4 (positive electrode terminal 172, negative electrode terminal 182) is measured during at least a time period from when the nut 2 takes its place on the fastened member 3 (bus bar 190) until fastening is finished. Based on the contact resistance measured between the fastened member 3 (bus bar 190) and the fastened member 4 (positive electrode terminal 172 and negative electrode terminal 182), whether or not there is the foreign material between the fastened member 3 (bus bar 190) and the fastened member 4 (positive electrode terminal 172 and negative electrode terminal 182) is determined.