The invention discloses a failure detection method and a failure detection device, which are used for detecting bridging defects of two conductors to be detected. The method comprises the following steps of: respectively arranging an output end on the two conductors to be detected, wherein the electric potential of the two output ends is equal; sequentially inputting constant detection current toany one conductor to be detected along detection points arranged in a preset path; detecting output current of the two output ends, and establishing a corresponding relationship between the output current at the output ends and the detection point positions based on the position information of the detection points and output current information of the two output ends; and judging whether the detection points have defects or not according to the corresponding relationship. The invention can effectively detect and position the bridging defects between metal interconnection lines in a semiconductor device, and improve the sensitivity and accuracy of positioning the defects.