An atomizer (100), the atomizer (100) comprising an atomizing head (3), a ventilation assembly (1), an e-liquid filling cap (2) and an e-liquid storage assembly (4); an upper end of the ventilation assembly (1) is detachably connected to the e-liquid filling cap (2); a lower end of the ventilation assembly (1) is sleeved on the e-liquid storage assembly (4) and partially accommodated in the e-liquid storage assembly (4); the atomizing head (3) is disposed at the lower end of the ventilation assembly (1), is accommodated in the e-liquid storage assembly (4), and is detachably connected to the ventilation assembly (1); an e-liquid filling channel (300) and an air-intake channel (200) are disposed in the ventilation assembly (1) and are mutually independent; the e-liquid filling channel (300) is axially disposed in the ventilation assembly (1); an e-liquid filling port (15) of the e-liquid filling channel (300) is located on a surface of an upper end of the ventilation assembly (1) near the e-liquid filling cap (2); the e-liquid filling channel (300) is connected to the e-liquid storage assembly (4); an exhaust port (122) which is connected to the air-intake channel (200) is further provided on the surface of the upper end of the ventilation assembly (1); when the e-liquid filling cap (2) is installed on the ventilation assembly (1), the exhaust port (122) is sealed by the e-liquid filling cap (2).