A nonvolatile memory device comprises a memory cell array, a page buffer, and a bit line connection signal controller. The memory cell array comprises a plurality of word lines and bit lines arranged in rows and columns, and a plurality of memory cells connected to the respective word lines and bit lines. The page buffer connects a selected bit line among the plurality of bit lines to the page buffer, applies a precharge voltage to the selected bit line, and senses a voltage of the selected bit line after developing of the selected bit line according to a bit line connection signal, during a read operation. The bit line connection signal controller changes the bit line connection signal according to a control signal, during the read operation.