A non-volatile memory device may include at least one string, at least one bit line corresponding to the at least one string, and/or a sensing transistor. The at least one string may include a plurality of memory cell transistors connected in series. The sensing transistor may include a gate configured to sense a voltage of the corresponding bit line. A threshold voltage of the sensing transistor may be higher than a voltage obtained by subtracting a given voltage from a voltage applied to read the corresponding bit line connected to a memory cell transistor to be read of the plurality of memory cell transistors.