A nonvolatile ferroelectric memory device amplifies a sensing voltage level of cell data with a CMOS threshold voltage reference in a main bitline, and decides cell data when a reference timing strobe is applied on a basis of a time axis. In a read mode, read data applied from a cell array block are stored in a read/write data register array unit through a common data bus unit. In a write mode, read data stored in the read/write data register array unit or input data applied from a read/write data buffer unit are stored in a cell array block through the common data bus unit. As a result, a sensing voltage of cell data is determined on a basis of the time axis, thereby improving a sensing margin.