The present disclosure relates to an atomizer includes an atomizing device and a liquid supply. The atomizing device includes an engaging part. The liquid supply includes a liquid chamber. The liquid supply includes a connecting end and a liquid outlet defined in the connecting end. The engaging part defines a liquid inlet through which tobacco liquid can flow into the atomizing device. The liquid supply further includes a sliding block slidable between a first position and a second position. When the sliding block is in the first position, the sliding block seals the liquid outlet; when the sliding block is in the second position, the liquid outlet is opened. The engaging part is capable of sliding along a predetermined track to form a snap-fit connection with the connecting end, and simultaneously driving the sliding block to move from the first position to the second position.