An atomizer and an electronic atomization device are disclosed. The atomizer includes: a housing, having an outer wall; and a mouthpiece, having an inner wall, and the inner wall defining a cavity. A plurality of anti-rotation grooves are defined on one of the inner wall and the outer wall, one or more anti-rotation ribs are arranged on the other of the inner wall and the outer wall, and the number of the anti-rotation grooves is greater than or equal to the number of the anti-rotating ribs. The housing is assembled with the cavity, and the one or more anti-rotation ribs are engaged in the corresponding one or more of the plurality of anti-rotation grooves.