To provide a semiconductor integrated circuit in which threshold voltage measurement of a nonvolatile memory cell can be conducted by linearly changing a word line selection level without directly driving a word line by a D/A converting circuit.

A nonvolatile memory (4), in which stored information is rewritable, is provided with drivers (33R1 to 33Rn) which drive word lines by reading operations and a first power supply circuit (39A) which supplies operating power to the drivers. In a test mode, the operating power supply voltages of the drivers generated by the circuit (39A) are controlled based on the conversion output voltage of the D/A converting circuit. When the threshold voltage of the nonvolatile memory cell is detected for device defect, it is possible to linearly change the operating power supply voltages of the drivers generated by the circuit (39A) in an approximate manner based on the conversion output voltage of the D/A converting circuit. Thus, no current driving capability is required to drive word line loads for the D/A converting circuit.