A toner cartridge for a printer includes a species detection key which forms a part of an outer shape of the cartridge and an IC chip which stores individual information, wherein a part of a harness for connecting to the IC chip or between the IC chip and a connector portion is mounted on the species detection key. A main body of the printer has a key receiving portion which mates with the species detection key. Thereby, the printer can detect erroneous attachment of a cartridge at early stage and surely cope with various types of cartridges requiring only compact space with the aid of its detection means.