An aroma diffuser is provided, including: a diffuser having a hollow housing, a heat conduction container disposed in the hollow housing, a resistor disposed under the heat conduction container, and a plugging device installed in a second opening of the hollow housing and electrically connected to the resistor and an aroma stone disposed in the heat conduction container that absorbs essential oil. The aroma stone can be disposed after the essential oil evaporates completely. The plugging device is a car plug that can be combined with an aroma stone used in a car or a USB device that can be combined with a mobile device, a notebook computer, a desktop computer or any appliance with a USB connection port. When supplied with power, the resistor generates heat, and the heat conduction container conducts the heat to the aroma stone for the aroma stone to diffuse scent.
