The invention provides a small humidifier. The small humidifier is mainly composed of a water filling nozzle, an upper cover, an adjusting ring, a shell, a mist outlet, a water storage chamber, a controller, an exhaust pump, an atomizing chamber, atomizing pieces, a backflow pipe, batteries, liquid conveying pipes, a backflow groove and a fan. The small humidifier is characterized in that the 12 atomizing pieces surround the outside of the atomizing chamber inside, the water storage chamber is arranged above the atomizing chamber and connected with the atomizing pieces through the four liquid conveying pipes, the adjusting ring and the mist outlet are arranged above the water storage chamber, the controller is arranged in the upper cover, the exhaust pump is arranged on the water storage chamber, two fans are arranged below the atomizing chamber and are overlapped to provide upward wind power, the four batteries are arranged outside the fans, and the upper cover and the shell respectively cover an upper structure and a lower structure inside, so that large mist outlet quantity can be output.