wall 212 f extends downward from the top face 194 c a buffer 214 c is provided for each of the position between the actuator 106 and the partition wall 212 a and between the actuator 106 and the side wall 194 b therefore the periphery of the actuator 106 is surrounded by the buffer 214 c a porous member 1005 b is provided inside the detection side ink chamber 213 b by providing the actuator 106 on the protruding part 214 f positioning for mounting the actuator 106 on the ink cartridge 180 j becomes easier when manufacturing the ink cartridge 180 j fig8 shows further another embodiment of the ink cartridge 180 using actuator 106 an ink cartridge 180 k shown in fig8 has a partition wall 212 a extends downward from the top face 194 c the container 194 is separated into a ventilation side ink chamber 213 a and a detection side ink chamber 213 b by the partition wall 212 g uneven part is provided on the top wall 194 c and two actuators 106 are mounted on the protruding part which protrudes inside the detection side ink chamber 213 b the concave part of the top wall 194 c works as a buffer 214 c which accepts bubble furthermore a porous member 1005 b is provided inside the detection side ink chamber 213 b by providing two actuators 106 on the protruding part 214 f detecting the ink consumption status mistakenly can be prevented the number of.