Disclosed is a micro droplet generator which comprises a lower space for containing a control panel, and an upper chamber for containing fluid medicine and including an nebulized area formed on a joining portion of the space and thereof. On the nebulized area there are provided an outer nozzle plate including tapered apertures and a piezoelectric element electrically coupled to the control panel. Activating the piezoelectric element will vibrate it to sufficiently mix the liquid medicine for developing fluid cavitation in the nebulized area, forms a stream of droplets from small particles of the fluid medicine and ejects the same therefrom, condenses the large particles of the fluid medicine due to collision therebetween, and drops the condensed liquid into the fluid medicine. Also, any malfunctioned component can be replaced individually.