Abstract: A transversal filter circuit including a plurality of tap circuits, each having a serial multiplication circuit having a simplified construction and not requiring a shift of decimal (binary) points of data during a partial product calculation and addition operation. The serial multiplier includes a bidirectional shift register for shifting a tap coefficient by a predetermined number of bits in one of two directions, a data input circuit, a partial product calculation circuit, an adding and holding circuit, and a control circuit. The control circuit alternatively changes the shift direction of the bidirectional shift register for shifting a tap coefficient and a data output direction of the data input circuit at each successive cycle. The partial product calculation circuit calculates a partial product of a tap coefficient from the shift register and the input data for a plurality of times defined by a bit number of the input data.