Disclosed are a semiconductor storage apparatus and a microcomputer incorporating the same. The semiconductor storage apparatus has a nonvolatile memory and a first sense amplifier comparing the level of a read-out signal read out from the nonvolatile memory with a first reference level. The semiconductor storage apparatus comprises a detector operable to output, when detecting that a difference between the level of the read-out signal and the first reference level is smaller than a predetermined level difference, a detection signal indicative of the difference being smaller than the predetermined level difference.