PURPOSE: To obtain a water-screening and chemical-resistant electric cable comprising lead laminate tapes, by removing part of the plastic layer of each of lead laminate tapes to expose each of the lead surfaces, overlapping the exposed parts of the lead surfaces, subjecting said parts to ultrasonic vibrations to weld said exposed parts together readily and positively.

CONSTITUTION: The plastic film layers 3, 3' on the lead laminate tapes 1, 1' where connection should be done are peeled and removed, opposite plastic film alyers are peeled and turned back, and the thus exposed lead tapes 10, 10' are overlapped. Ultrasonic vibrations are applied onto the overlapped parts to produce frictional heat to the interface of the lead tapes so as to weld them, and after that, if required, the turned back plastic layers 2, 2' are restored to the original positions and fused to complete the connection.