An atomizer includes a motor mounted in a housing. First and second cylinder units are received in the housing. The first cylinder unit includes a first piston and a first coupling bearing connected to the first piston. The second cylinder unit includes a second piston and a second coupling bearing connected to the second piston. An eccentric transmission shaft of the motor extends through the first and second coupling bearings of the first and second cylinder units. The first and second pistons of the first and second cylinder units move reciprocatingly when the motor operates. An intake check valve is mounted in an intake passage between an intake port of the first cylinder unit and an inlet of the housing. An outlet check valve is mounted in an outlet passage between an outlet port of the second cylinder unit and an outlet of the housing.
