Abstract: A conductor tester including two contour-identical parts of a main unit and a remote unit is used to test and indicate present condition of conductors. Both the main and the remote units are formed at two ends with high and low raised portions that are provided with fastening means for the two units to detachably connect to each other to form a compact unit. The high and low raised portions are provided at side walls with notches that are electrically connected to internal circuits of the main and the remote units, and at inner walls between the high and low raised portions with light-emitting diodes.