An electrical insulating property tester includes a guaranteed voltage applying unit for applying a guaranteed voltage to a running line provided with an electrical insulating layer around an electrical conducting wire, a grounding unit arranged downstream of the guaranteed voltage applying unit, for grounding the running line to thereby remove electric charge electrostatically induced on the running line, and a test voltage applying unit arranged downstream of the grounding unit, for applying a test voltage lower than the guaranteed voltage to the running line, to thereby detect a leakage current value.
展开▼
