A scent diffuser contains: a body, a power connection unit, a pump, and a diffusing device. The body includes an accommodation chamber and a first opening. The power connection unit is housed in the accommodation chamber. The pump includes an air inflow segment and an air outflow segment. The diffusing device is accommodated in the body and includes a cap, a nozzle, a spraying member, a holder, and a spray hose. The cap has a first orifice, a second orifice, and a third orifice. The spraying member has a receiving groove, a suction mouth, and an outlet. The nozzle has a shrinkage conduit and a narrow conduit, and a slit is defined between the nozzle of the diffusing device and the receiving groove of the spraying member. The holder has a connection portion, and the cap is coupled on the holder.
