A nebulizer characterized in being provided with: an inner tube, which is disposed coaxially with an outer tube in which a nebulizing outlet is formed and which, together with the outer tube, forms a gas channel therebetween; a sample channel, which is formed inside the inner tube and through which a liquid sample to be nebulized flows; and a reticular membrane disposed with a gap from the sample outlet that is formed at one end of the inner tube and in which multiple holes, through which liquid sample drops flowing out from the sample outlet pass along with a gas, are formed. Using the nebulizer, the particle size of the nebulized liquid droplets can be made uniformly fine over a broad range of sample liquid flow volumes while retention of sample liquid in the nebulizer is reduced.