Provided is a method of increasing sensitivity of an electric field sensor, a storage unit and a reproducing method. The storage apparatus includes a ferroelectric recording medium, an electric field sensor including a source region, a drain region and a resistance region electrically connecting the source region to the drain region and having a resistance, which varies according to an intensityof an electric field due to a polarization voltage of an electric domain of the recording medium, a voltage applying unit applying a drain voltage between the source region and the drain region, and a reproducing signal detection unit including at least one negative resistor installed in an electric circuit connecting the drain region to the voltage applying unit, and detecting a change in a voltage between the drain region and the at least one negative resistor.