Setting of a parameter of a defect inspection tool is based on trial and error in which effects are confirmed one by one and set, and the setting requires a high technique and is significantly inefficient. The present invention is to provide an inspection method and an inspection tool capable of solving such a problem and of setting the parameter (hereinafter, referred to as an inspection parameter) required for detecting the defect easily. In order to solve the problem, a defect inspection tool according to the present invention is provided with image obtaining unit for obtaining an image by applying an electron beam to a specimen; an image processing unit for performing a calculation process by using each predetermined inspection parameter group based on the image obtained by the image obtaining unit; and a parameter tuning unit for performing a process to determine an effective inspection parameter group from calculation results by the calculation process and narrowing down an inspection parameter group range by repeating the process for a plurality of images obtained by the image obtaining unit, and is provided with a configuration to detect the defect by using the inspection parameter group narrowed down.