A plurality of signal processing elements are cascade-connected to form a signal processor having three signal paths. The signal processor is a small-sized device which can be shared by sum-of-products calculation and division. In each signal processing element, first and second shifters and an adder-subtracter are used for performing shift addition for multiplication of a variable by a constant which is a basis of the sum-of-products calculation. The adder-subtracter and a third shifter for shifting a result obtained by the adder-subtracter are used for performing subtraction and shifting for obtaining a partial quotient and a partial remainder of division. The partial quotient thus obtained is transferred to the signal processing element in the next stage through a flag holding circuit.