The present invention discloses a failure detection method and a failure detection apparatus for detecting a defect in an electrical conductor. The failure detection method includes: providing at least two output terminals on the electrical conductor under test, the at least two output terminals having identical electric potentials; inputting a constant detection current sequentially to detection points arranged on the electrical conductor under test along a predetermined path; detecting an output current at one or more output terminals of the at least two output terminals; building a correspondence relationship between the detected one or more output currents at the one or more output terminals and positions of the detection points, based on information of the positions of the detection points and information of the detected one or more output currents at the one or more output terminals; and determining from the correspondence relationship whether the detection points have a defect. The failure detection method according to the invention can precisely locate defects; and uses a charged particle beam as the detection current source to avoid the size limitation of irradiation points, thereby satisfying the requirement for failure analysis in a small size.