Atomization unit and atomization device

The atomization unit comprises a shell, a mounting seat, a base and an ultrasonic atomization piece, one end of the shell is provided with an opening, the other end of the shell is provided with a liquid inlet hole, one side of the shell is provided with a spray hole, the base blocks the opening of the shell, the mounting seat is embedded into the shell, the mounting seat and an inner cavity of the shell are in close fit, the contact area of the mounting seat and the inner cavity of the shell is large, and the ultrasonic atomization piece is arranged on the base. The connection stability is high, a liquid storage cavity communicated with the inner cavity of the shell is defined in the installation base, the position, corresponding to the spraying hole, of the installation base is concavely arranged inwards in the direction away from the spraying hole to form a groove, a mist outlet communicated with the liquid storage cavity is formed in the groove, and the ultrasonic atomization piece is placed in the mist o