An actuator can selectively take a first state wherein a volume of a pressure chamber is V1 and a second state wherein the volume of the pressure chamber is V2 larger than V1. The actuator changes from the first state to the second state and then returns to the first state to eject ink from an ejection port. A proper oscillation period Ts of an oscillation generated by integral deformation of the actuator and the pressure chamber when ink is ejected from the ejection port, and a proper oscillation period Td of ink filling up a first partial passage leading from an outlet of the pressure chamber to the ejection port in an individual ink passage, satisfy a condition that Ts/Td is not less than 0.36 and not more than 0.90; or not less than 1.1 and not more than 1.7.