The present technology relates to an electronic device. A memory device that controls a voltage applied to each line to prevent or mitigate a channel negative boosting phenomenon during a sensing operation includes a memory block connected to a plurality of lines, a peripheral circuit configured to perform a sensing operation on selected memory cells connected to a selected word line among the plurality of lines, and control logic configured to control voltages applied to drain select lines, source select lines, and word lines between the drain select lines and the source select lines among the plurality of lines, during the sensing operation and an equalizing operation performed after the sensing operation. The control logic controls a voltage applied to an unselected drain select line according to whether a cell string is shared with a selected drain select line among the drain select lines, during the sensing operation.