An atomizer, including an e-liquid tank, a connector, a silicone sleeve, and an atomization element. The connector is disposed in the e-liquid tank. The silicone sleeve is disposed around the connector. The atomization element is in threaded connection to the e-liquid tank. The atomization element includes atop end provided with an e-liquid inlet. The top end is disposed in the silicone sleeve whereby the e-liquid inlet is sealed; one end of the silicone sleeve extends out of the e-liquid tank. When the atomization element is short of e-liquid, lifting up the silicone sleeve to expose the e-liquid inlet, so as to inject the e-liquid into the atomization element.