A nebulizer includes a main body unit, an atomization unit, and a breath detection unit, which is a function unit for realizing an additional function of the nebulizer. The main body unit and the atomization unit are separable. The atomization unit includes a storage section for storing the medicinal solution, and an atomizing section for spraying the medicinal solution by atomizing the medicinal solution in the storage section. The main body unit includes a control circuit for performing control to operate the atomizing section. The breath detection unit is attachable between the main body unit and the atomization unit.