A plasma generator generates atmospheric pressure, low temperature plasma (cold plasma), and includes a first electrode; a second electrode opposing the first electrode such that a bottom surface of the first electrode faces a top surface of the second electrode, the second electrode arranged so as to define a predetermined gap between the planar bottom surface of the first electrode and the planar top surface of the second electrode; a dielectric layer that is disposed on at least a part of the bottom surface of the first electrode having a relative permittivity between 2 and 500, and a thickness of 3 mm or less; and a power supply configured to supply electrical power to the first and second electrodes at a predetermined voltage and frequency, such that, based on the predetermined gap between the first electrode and the second electrode, atmospheric pressure, low temperature plasma is generated.