Resistive memory device for writing data and operating method thereof

A resistive memory device includes a resistive cell connected between a first bit line and a first source line, a reference cell including a reference resistor and connected between a second bit line and a second source line, and a write driver connected to the first bit line or the first source line, connected to the second bit line or the second source line. The write driver includes a comparator configured to compare previous data written in the resistive cell with the target data by comparing a voltage of the first source line with a voltage of the second source line or comparing a voltage of the first bit line with a voltage of the second bit line, and determine whether the target data is written in the resistive cell after comparing the previous data with the target data.