PURPOSE: To simplify the circuit construction by choosing one of plural multiplied number by means of a balance change over switch as well as choosing one of plural multipliers corresponding to the chosen multiplied, then multiplying each other.

CONSTITUTION: One balance change over switch 7a is pressed when, for instance, span adjusting is carried out for a first balance parts 1A. As a result, a signal "1" is fed to one input terminal of an AND gate 6a. When the object of a certain weight for the first balance part 1A is placed on a scale 2a, a signal indicating this weight is fed to the other input of the AND gate 6a to be supplied to a multiplier 9 as a multiplied number. A signal "1" is also fed to one input of an AND circuit 11a so that the output from one digital switch 10a is fed to the multiplier 9. The digital switch 10a is so adjusted that multiplication result indicates a certain weight, considerably simplifying the circuit construction.