A finite impulse response (FIR) filter for wave-shaping digital quadrature amplitude modulation (QAM) symbols is disclosed, in which multipliers are replaced with multiplexers, the replaced multiplexers are utilized to receive the symbols directly from a symbol encoder without zero (0) interpolations, and the critical path is reduced by shifting the position of a delay device. The filter includes a first FIR means for delaying the externally inputted symbol data, and for utilizing the delayed symbol data as selection signals to sum up the selected multiplication product (selected from among products obtained by multiplying the symbol values by a pre-set filter tab coefficient) and the selected value selected by a first multiplexing means. A second FIR means delays again the delayed symbol data of the first FIR means, and utilizes the delayed symbol data as selection signals to sum up the selected multiplication product and the output value of the first FIR means.