An ink cartridge and an ink cartridge identifying apparatus are provided which reliably allow only standard, proper ink cartridges to be loaded. An ink cartridge to be loaded into a printer is provided which has a predetermined projected and recessed pattern portion formed on an outer surface thereof and which has a first electrode portion arranged on the projected and recessed pattern portion. The first electrode portion is positioned to be selectively engageable with a second electrode portion, which is arranged on a pattern matching portion which is fixed to a press rod arranged on the printer main body. First and second electrode portions are arranged on the projected and recessed pattern portion and the pattern matching portion to be selectively engageable, and an identification signal is generated when matching first and second electrode portions are engaged. The projected and recessed pattern portion and the pattern matching portion may be shaped into characters/symbols, graphics, or the like.