A container having a liquid detecting function includes a cartridge case 101 having a sending passage for sending out a liquid stored therein, buffer chambers 122 and 123 disposed in the vicinity of the end of the sending passage, and a sensor unit 200 disposed to face on the buffer chambers. A sensor chip 230 provided in the sensor unit includes a sensor cavity 233 communicating with the buffer chambers, a vibration plate 233 closing an opening side of the sensor cavity opposite to the side communicating with the buffer chambers, and a piezoelectric element 234 which is disposed on the surface of the vibration plate opposite to the surface facing the sensor cavity, emits a vibration wave to the sensor cavity and the buffer chambers through the vibration plate, receives a reflected wave returning from the buffer chambers through the vibration plate, and then converts the reflected wave into an electrical signal. The compliance values of the buffer chambers 122 and 123 are set to be ten times greater than the compliance value of the sensor cavity.