The invention relates to an air cleaner for a vehicle which can be installed on the rear of the vehicle, which includes a suction pipe provided with a slit having a length corresponding to a width of the vehicle, an air pump connected to inside of the suction pipe by a guide pipe, and a filter means connected to the air pump. The air cleaner is operated in a way of sucking exhaust gas and fine dust generated from an exhaust line of the vehicle together with fine dust and dust particles generated around tires of the vehicle during driving of the vehicle, removing them, and then discharging purified air to the atmosphere. The air cleaner can effectively remove the fine dust and various-shaped dust particles directly and indirectly generated from the vehicle, and remarkably reduce generation of fine dust by considerably suppressing diffusion of fine dust into atmosphere.