Abstract: A switch assembly of a main body of an electronic cigarette has a casing, a control unit, a switch element and a locking element. The switch element has an actuating element. The locking element is rotatable relative to the casing, and has a stop segment. A position of the stop segment may be adjusted by rotating the locking element. When the locking element is rotated to make the stop segment abut the switch element, the switch element cannot be pressed to actuate the control unit. No matter at what angle the main body is disposed, the locking element does not tend to be rotated and unlocked by its weight as the locking element is not screwed to the casing and is rotated at the same position. Therefore, the locking element is effectively kept locked to prevent the electronic cigarette from being switched on accidentally.