A cartridge includes a casing, a printing material containing portion, a printing material flow path and first and second insertion holes formed in a front face of the casing. A rod used for detection of the out-of-printing material state is inserted into the first insertion hole, and a printing material supply tube is inserted into the second insertion hole. The first insertion hole is located on the front face at a middle position between a first side face and a second side face of the casing.