An image forming apparatus includes an environment obtaining portion, a storage portion, an environment determination portion, a firmware selection portion, and a firmware rewriting portion. The environment obtaining portion obtains environment information from an environmental sensor. In the storage portion, an environmental condition table and a firmware table are stored. In the environmental condition table, in association with registered environment information indicating a specific environment, identification information for identifying the specific environment is stored. In the firmware table, in association with the identification information, firmware that corresponds to an environmental condition indicated by the identification information is stored.The environment determination portion determines whether the obtained environment information corresponds to the registered environment information. Based on the firmware table and on the identification information, the firmware selection portion selects firmware that corresponds to the identification information. The firmware rewriting portion rewrites currently-used firmware with the selected firmware.