To surely control a discharging amount by arranging a shaking part shaking off residual liquid at the tip of a nozzle by vibration in a dispenser type liquid injector provided with the nozzle for discharging liquid at the tip and used for injecting a very small fixed amount of oil to a precision machine part.
In a liquid injector 1, liquid is dropped from a tip 2a of a nozzle 2 so as to be supplied to a machining object when a pneumatic pressure is applied to a cylinder 3 storing liquid inside from a compressor 6 via a tube 5. In this case, a shaking part 7 is provided in the liquid injector 1, so that liquid remaining at the tip 2a of the nozzle 2 can be shaken off by vibration. The shaking part 7 is constructed by using a piezoelectric element 7c, which is mounted around the nozzle 2 via a fixed base 9, while four outer circumference electrodes 7a, 7b are alternately stuck to the outer circumferential face of the piezoelectric element 7c, and a single inner circumferential electrode is formed on the inner circumferential face of the piezoelectric element 7c so as to serve a grounding terminal.