An inspection apparatus for a filter cigarette FT having a perforation line (6) in the outer circumferential surface of a filter (4) for introducing the outside air has a filter socket assembly (86) that is capable of receiving the filter (4) and includes a ring holder (124) defining in the inside an end chamber for surrounding the mouthpiece of the filter (4) and a surrounding chamber for surrounding the outer circumferential surface of the filter (4) including the perforation line (6), a guide pipe (102) for supplying a compressed fluid of the given pressure into the surrounding chamber of the ring holder (124), and a guide pipe (100) that outputs the pressure in the end chamber; and a pressure sensor for detecting the pressure outputted from the guide pipe (100) that outputs the pressure in the end chamber.