A part information restoration method is adapted to an electronic apparatus having first and second parts which are replaceable and are provided with a nonvolatile memory for storing part information unique to the part. The method includes storing, in a first nonvolatile memory of the first part, part information of the first part, and saving part information of the second part as a first reference information at least when replacing the second part, storing, in a second nonvolatile memory of the second part, the part information of the second part, and saving the part information of the first part as second reference information at least when replacing the first part. The method restores the first reference information in the second nonvolatile memory or restores the second reference information in the first nonvolatile memory, after replacing the first or second part.