Abstract: Provided is a data read circuit that can execute data reading under a proper reference voltage in the event that element characteristics have been changed due to aged deterioration. When a sample memory cell (10a) is selected, a memory transistor (26a) in which no electrons are injected into its floating gate, enters ON state. At this time, a voltage (V.sub.22) is inputted to an input terminal (22) of a sense amplification (18), and a control circuit (13) detects the voltage (V.sub.22) to store it as a digital signal. On the other hand, when a sample memory cell (10b) is selected, a memory transistor (26b) in which electrons are injected into its floating gate, does not enter ON state. As a result, a voltage (V.sub.11) is inputted as it is, to the input terminal (22). The control circuit (13) detects the voltage (V.sub.11) to store it as a digital signal. Based on the two digital signals, the control circuit (13) sets a reference voltage (V.sub.