An analyzing apparatus of the present invention includes a cassette unit (20) for generating a cassette identification signal identifying a type of a cassette (21), a sample holder (8) having an insertion hole (83) and a ring shaped pedestal (82), a transport section (23) for transporting the sample (S), a sample holder identifying section (35) for generating a sample holder identification signal identifying the type of the sample holder appropriate to the diameter of the sample to be placed, and a determining section (40) for determining, based on the cassette identification signal and the sample holder identification signal, whether or not the diameter of the sample to be accommodated in the cassette (21) and the diameter of the sample to be placed on the pedestal of the sample holder (8) match with each other.