An atomizer nozzle assembly for producing an extrafine mist of liquid includes a nozzle assembly, with a liquid passage hole of each nozzle tip of the assembly extending along a longitudinal axis of the nozzle tip. A front end opening of each liquid passage hole is centrally formed in the front end face of each nozzle tip. The angle of taper of a front tapered portion of each nozzle tip is 16.degree.-24.degree.. With the above arrangement, it is possible to produce a substantially ultrafine mist when the atomizing operation is started and it is also to produce an ultrafine mist having a constant particle diameter during a rise in the initial pressure of compressed air immediately following the start of atomization.