In an OTP memory storing a one-bit of the data by two gate insulating film destruction type nonvolatile memory cells where a same bit line is connected and different word lines are connected, writings and readings of the data for selected two nonvolatile memory cells constituting one-bit are performed by simultaneously selecting the selected two nonvolatile memory cells, and verifications for the selected two nonvolatile memory cells are performed by individually selecting one and the other of the selected two nonvolatile memory cells one by one.