In an operating method in a read or verification operation of a nonvolatile memory device, selected bit lines are precharged to a logic high level and, at the same time, unselected bit lines are discharged to a logic low level. The selected and unselected bit lines are connected to respective memory cell strings and, concurrently, word lines are supplied with a pass voltage. The connection between the selected and unselected bit lines and the respective memory cell strings is shut off and, concurrently, a selected word line is supplied with a ground voltage. The selected and unselected bit lines and the respective memory cell strings are coupled together and, concurrently, a selected word line is supplied with a reference voltage and an unselected word line is supplied with the pass voltage.