The invention relates to an aroma diffuser which comprises a shell, wherein an air inlet is formed in the bottom of the shell; an air outlet is formed in the top of the shell; an atomizing chamber communicated with the air outlet is arranged in the shell; an air channel is formed between the atomizing chamber and the air inlet; an air blower used for blowing the air into the atomizing chamber is arranged in the air channel; an atomizing cavity is formed in the bottom of the atomizing chamber; an atomizing blade is arranged below the atomizing cavity; a circuit board is arranged in the shell; a key switch and a connector which is used for connecting a portable power source are arranged on the shell; the atomizing blade, the circuit board, the key switch and the connector are electorally connected. The aroma diffuser favorably accords with the social trend that the portable power sources are more and more commonly accepted by social groups, so that the flexibility of application positions of the aroma diffuser is greatly improved.