ce 115, which constitute the power-line carrier communication apparatus 100 of FIG. 3, FIG. 6, FIG. 7, are constituted by a poly-phase filter with reference to FIGS. 12A, 12B, FIG. 13A, and 13B. FIG. 12A is a block diagram for representing a band-synthesizing filter bank circuit which is constituted by general-purpose FIR filters, and FIG. 12B is a block diagram for showing a band-dividing filter