The present invention is to propose an data erasing method, a memory apparatus, and a data erasing circuit which are able to reduce the time required to boost the potential of the semiconductor substrate thereby to reduce the time required to erase data. Namely, a memory apparatus having a data erasing circuit that erases stored data by applying an erasing voltage between a semiconductor substrate and a control gate so as to discharge electric charges accumulated in a floating gate is disclosed. In this case, the data erasing circuit boosts a potential of the semiconductor substrate side while placing the control gate into its floating state; and applies an erasing voltage between the semiconductor substrate and the control gate to make the potential of the control gate to a predetermined potential.