Atomizer and aerosol generating device

The embodiment of the invention provides an atomizer and an aerosol generating device.The atomizer comprises a liquid storage space, a ventilation pipeline, a heating body, a ventilation channel and a first sealing part, and the liquid storage space is used for storing an aerosol generating substrate; the ventilation pipeline is provided with an atomization space, a liquid discharging opening penetrating through the side wall of the atomization space is formed in the ventilation pipeline, and the liquid discharging opening communicates with the liquid storage space; the heating body is arranged in the atomization space; the ventilation channel is provided with a ventilation outlet; the first sealing piece is arranged between the heating body and the side wall of the atomization space, the first sealing piece comprises a first guide part, and ventilation bubbles formed at the ventilation outlet can be guided to the liquid discharging opening through the first guide part and enter the liquid storage space throu