Electrolysis apparatus

An electrolysis apparatus (1) includes an outer cylinder (2) having an inlet (3) and an outlet (4) on a side surface (2a) of the cylinder; positive electrode plates connected to a first base at equal intervals and arranged near one opening of the inlet (3) and the outlet (4); a negative electrode plates connected to a second base at equal intervals and arranged near an opening of the other of the inlet (3) and the outlet (4); and insulative positive electrode-side spacers (20) each disposed between every adjacent positive electrode plates, or insulative negative electrode-side spacers (30) each disposed between every adjacent negative electrode plates. One opening is positioned radially outward with respect to spaces defined between the positive or negative electrode plates. Each positive or negative electrode-side spacer (20, 30) is provided with an inclined surface inclined with respect to the central axis of the outer cylinder (2), for guiding a flow of a fluid to be processed from one opening toward the c