One of the present authors (H.D.)previously made a comparison to measure an NRM(natural remanent magnetization)of a rock sample between the measurements by means of an astatic and a spinner magnetometers and he noticed that 24 varia-tions may be considered of the spin-holding of a test specimen to be determined its NRM by means of a spinner magnetometer (Domen 1979).That is to say, the spec-imen is revolved successively about 6 axes