An atomizer, comprising: a housing, wherein an air outlet channel is formed in the housing; and an atomizing assembly assembled in the housing and comprising a base and an atomizing core inserted in the base, wherein the base comprises a top wall facing the air outlet channel and a side wall intersecting with and connected to the top wall; wherein an atomizing channel in communication with the air outlet channel is defined between the side wall and the atomizing core, the atomizing channel is located in an axial direction of the air outlet channel, and an air inlet in communication with the atomizing channel is provided; wherein the atomizing core comprises an atomizing surface parallel to the axial direction of the air outlet channel, the atomizing surface is relatively spaced apart from the side wall, and the atomizing channel is defined between the atomizing surface and the side wall; wherein the atomizing assembly further comprises an electrode, the atomizing core further comprises a heating member, one end of the electrode is electrically connected to the heating member, and the other end of the electrode penetrates through the side wall and is relatively exposed on an outer surface of the side wall; wherein the base comprises a base body and a holder, the atomizing core and the holder are both inserted in the base body, one end of the holder abuts against the atomizing core, the other end of the holder is the side wall characterized in that the air inlet in communication with the atomizing channel is provided on the side wall and the electrode fixedly penetrates through the end of the holder provided with the air inlet. a housing, wherein an air outlet channel is formed in the housing; and an atomizing assembly assembled in the housing and comprising a base and an atomizing core inserted in the base, wherein the base comprises a top wall facing the air outlet channel and a side wall intersecting with and connected to the top wall; wherein an atomizing channel in communication with the air outlet channel is defined between the side wall and the atomizing core, the atomizing channel is located in an axial direction of the air outlet channel, and an air inlet in communication with the atomizing channel is provided; wherein the atomizing core comprises an atomizing surface parallel to the axial direction of the air outlet channel, the atomizing surface is relatively spaced apart from the side wall, and the atomizing channel is defined between the atomizing surface and the side wall; wherein the atomizing assembly further comprises an electrode, the atomizing core further comprises a heating member, one end of the electrode is electrically connected to the heating member, and the other end of the electrode penetrates through the side wall and is relatively exposed on an outer surface of the side wall; wherein the base comprises a base body and a holder, the atomizing core and the holder are both inserted in the base body, one end of the holder abuts against the atomizing core, the other end of the holder is the side wall characterized in that the air inlet in communication with the atomizing channel is provided on the side wall and the electrode fixedly penetrates through the end of the holder provided with the air inlet.