An inhaler has a cap body (150) for defining a flow path (101) through which an airflow moves and having, formed in it, first and second air inhalation openings (152a, 152b) for introducing outside air into the flow path (101) from the outside of a nebulizer (100A) an air inhalation valve (140) for opening and closing the first air inhalation opening (152a) by using the difference in pressure between the flow path (101) and the outside of the nebulizer (100A) and a shielding section (132) capable of selectively shielding either of the first and second air inhalation openings (152a, 152b). The inhaler is configured to be switchable between two states that are a first state where the second air inhalation opening (152b) is shielded by the shielding section (132) and outside air can be introduced through the first air inhalation opening (152a) by using the pressure difference and a second state where the first air inhalation opening (152a) is shielded by the shielding section (132) and communication between the flow path (101) and the outside of the nebulizer (100A) through the second air inhalation opening (152b) is constantly maintained. The construction enables the presence and absence of the air inhalation valve to be switched by simple operation.
