A measurement unit obtains, when a droplet ejected from an ejecting head adheres to an electrode of a crystal oscillator, a viscosity and a mass of the droplet on the basis of a changed value in resonance frequency and of a resonance resistance of crystal oscillator. Measurement unit then supplies to a control unit droplet information ID showing the obtained viscosity and mass. Control unit determines, on the basis of the viscosity and the mass included in droplet information ID, an appropriate drive waveform to be supplied to ejecting head.