A non-volatile memory device includes: one or more memory blocks including a plurality of memory cells connected to a plurality of word lines, and a plurality of memory cell strings; a page buffer unit; one or more pass units including a plurality of pass transistors that may supply operation voltages to the plurality of word lines; one or more monitoring units including one or more monitoring pass transistors connected to the plurality of pass transistors; a voltage generator that may supply activation voltages to a first pass transistor, in which a leakage current is to be measured, and to the one or more monitoring pass transistors; and a control logic that may control the voltage generator to generate the activation voltages by using a voltage control signal and detect the leakage current based on monitoring voltages output from the one or more monitoring pass transistors.