Abstract: An electronic counting balance for deriving the number of items from a measured weight of the items through an arithmetic operation including a weight measuring unit, first and second unit-weight memories for storing two kinds of unit weights, a calculator for estimating the number of items replenished on the weight measuring unit, an inputting unit for inputting a variation coefficient of the items to be counted, a maximum addable number calculator for calculating the maximum number of the items without errors in counting, first and second comparators for comparing the maximum number of items with an estimated number of items, a sampling data memory for storing the number estimated by the calculator and data relating to the weight of the replenished items, and a unit weight calculator for estimating two kinds of unit weights in order to renew the contents of the first and second unit weight memories.