A method for testing a multicore cable that includes a single common shield covering plural insulated wires. The testing method includes inputting a test signal, by capacitive coupling, to an end portion of the insulated wire under test among end portions of the insulated wires exposed at one end of the multicore cable, and measuring voltages of output signals output by capacitive coupling respectively from end portions of the insulated wires exposed at the other end of the multicore cable, and identifying the other end portion of the insulated wire under test based on the measured voltages. The voltages of output signals are measured in a state that an output variation reduction capacitive element is connected in series with a coupling capacitance generated by the capacitive coupling.