The present invention is directed to an ink supply device having an ink cartridge and a cartridge mount. The ink cartridge has an ink supply portion and an air intake portion. The cartridge mount has a first projection and a second projection. When the ink cartridge is inserted into the cartridge mount, the first projection opens the ink supply portion, and the second projection opens the air intake portion. The second projection has an operating piece, a guide path for receiving the operating piece, and a spring for exerting force on the operating piece. The second projection contacts the air supply portion prior to the first projection contacting the ink supply portion, and the guide path receives the operating piece after the second projection contacts the air supply portion.