To provide a phase contrast microscope capable of overcoming an optical effect of an observation target on a phase contrast image, a control apparatus for a phase contrast microscope, and a control method for a phase contrast microscope. A special Preferred Inter-exchange Carrier category associated with the IN service is specified in the subscriber’s database in the ANSI-41 Home Location Register. The cushion is designed and positioned so that, when the belt is worn, the free end portion of each flange bears on the corresponding iliac crest of the person, and the joining area is in contact with the area comprising the upper portion of the sacrum and the lower portion of the lumbar vertebrae.