An atomizer in an electronic cigarette is disclosed including an aerosol outlet tube; an air inlet tube; a heating element; an atomizing shell and a heating base; the air inlet tube is sleeved on the aerosol outlet tube and a first air inlet passage is formed between the air inlet tube and the aerosol outlet tube; a first aerosol outlet passage is formed inside the aerosol outlet tube; the heating element is disposed in the heating base; the atomizing shell is sleeved on the heating base; a second air inlet passage and a second aerosol outlet passage are spaced and arranged between the atomizing shell and the heating base, along a circumferential direction of the heating base; the first air inlet passage and the second air inlet passage are communicated to allow exterior air to pass through then to flow into the heating base.