The object of the present invention is to provide a bolt that effectively prevents gouging, seizure and racing between the bolt and nut without the aid of a guide boss and is effective when combined with the case nut. The object can be attained by providing a bolt having a threaded shank portion wherein a plural number of notched faces slanting toward the end of the threaded shank portion at an angle ranging from ±15° to ±80° toward the axis of the threaded shank portion, are formed at the beginning of the thread part of the threaded shank portion.