An aroma diffuser using an aroma capsule is disclosed to include a hollow housing including a first opening on a top side thereof, a second opening on a bottom side thereof and an integrated holder member downwardly inwardly extended from a top side thereof and defining therein a holding chamber facing toward the first opening, a heat conduction device mounted in the holding chamber, and a heating element mounted at a bottom side of the heat conduction device and kept in contact with the heat conduction device. Thus, an aroma capsule can be placed in the holding chamber and heated by the heating element to release fragrant vapor. After the aroma contained in the aroma capsule is used up, the aroma capsule can be replaced conveniently and rapidly.
