The present invention discloses an atomizer and an E-cigarette thereof, which use a holding portion movably provided on a terminal to achieve securing of a heating element, such that a user uses only hands for operation but without the help of an additional mounting tool. The present invention also discloses an atomizer and an E-cigarette thereof, which can adjust a dimension of a bore for mounting a heating wire by fitting a securing head with a sleeving, and thus various heating wires having different diameters can be mounted, such that the heating wires can be quickly and conveniently mounted, thereby achieving easy operation and good user experience.