The invention relates to a semiconductor element used for a nonvolatile semiconductor storage device or the like, a semiconductor storage device using the same, a data writing method thereof, a data reading method thereof and a manufacturing method of those, and has an object to provide a semiconductor element in which scaling and integration of cells are possible, storage characteristics of data are excellent, and reduction in power consumption is possible, a semiconductor storage device using the same, a data writing method thereof, a data reading method thereof, and a manufacturing method of those. A pn junction diode GD with a ferroelectric gate as the semiconductor element includes a gate electrode formed on a ferroelectric film, an inversion layer formation region in which an inversion layer is formed in a semiconductor substrate below the ferroelectric film according to a polarization direction of the ferroelectric film, a cathode region formed on one of both sides of the inversion layer formation region, and an anode region formed on the other of both the sides.