In a nonvolatile memory device (4) provided in a semiconductor device, when data is erased based on a band-to-band tunneling scheme, supply of a boosted voltage to a memory cell (MC) to be erased is ended when a condition that an output voltage (VUCP) of a charge pump circuit (52) has recovered to a predetermined reference voltage is satisfied and additionally a condition that a predetermined reference time has elapsed since start of supply of the boosted voltage (VUCP) to the memory cell (MC) to be erased is satisfied.