The present invention relates to a handheld aroma diffuser having a body. The body has a body housing, a protective rear casing and a battery protecting casing that are respectively connected to the body housing in a detachable manner. A placing groove and a battery groove are disposed on the body housing. An atomizing device is contained in the placing groove. A battery device is contained in the battery groove, and the battery device is electrically connected to the atomizing device. The protective rear casing covers the placing groove, and the battery protecting casing covers the battery groove. A mist discharge orifice communicated with the placing groove is disposed on the body housing and connected to the diffusion orifice of the atomizing device in an abutted manner. The atomizing device of the present invention is replaceable to lengthen the service life of the aroma diffuser and reduce use cost.
