Abstract: In this paper, the test method and the computation formula of eccentric errors in vertical axes series are briefly described, and the precision of the formula is discussed as well. This paper also presents the result of the calculation of the eccentric element (f) by means of the observed data and the mean value and variance are computed by using three method on the same instrument. Not only normal examination, gross error examination but also variance examination, are made with respect to measuring errors. Finally, while relevant data are analysed by way of variance, a comparison of the three methods is made with regard to their precision, and the applicability of each method is also analysed.