Abstract: A method for determining an object of a test for verifying the lightning protection adequacy of a fastening part includes: a structural pattern population generating step of generating a population of structural patterns identified by a combination of a plurality of properties of the fastening part; a section extracting step of extracting those sections which are disposed in a wet area of the aircraft where fuel or fuel vapor is present, from the sections of a fastening member, for each of the structural patterns of the population; a group setting step of setting a group of structural patterns of the same predetermined properties for each of the sections; and a representative pattern selecting step of selecting a representative pattern representative of the group from the structural patterns belonging to the same group. The structural pattern narrowed down through the steps is determined as the test object.