A method accurately inspects whether an IC inlet to be inspected is non-defective or defective in a state in which a large number of IC inlets are formed over an insulating film. The inspection of IC inlets formed over an insulating film is performed by transmitting microwaves to the IC inlets from antennas. To selectively irradiate the microwaves to only one IC inlet to be inspected out of a large number of IC inlets that are formed over the insulating film, a radio-wave absorbing plate is inserted between the insulating film and the antennas, and the microwaves are irradiated to the IC inlet through a slit formed in the radio-wave absorbing plate. The radio-wave absorbing plate is configured such that the slit, which is substantially equal to the IC inlet in size, is formed in a portion of a planar plate that is formed of a radio-wave absorber.