Disclosed is an air purifier with a small size, having an excellent air purifying capacity, capable of preventing a large amount of ozone from being generated, the ozone harmful to a human body. The air purifier includes a case, a pair of discharge electrodes provided at upper and lower parts of the case, a ground electrode provided between the pair of discharge electrodes, a pair of insulating dielectric layers provided on upper and lower surfaces of the ground electrode, and a power source coupled respectively to the ground electrode and the discharge electrode so as to supply voltage thereto.