NOVELTY - A control apparatus of biological water treatment apparatus comprises anaerobic tank influent volume control signal output unit to output signal which makes amount of bypass inflow to-be-processed water of to-be-processed water as predetermined value, amount detection unit of outflow phosphoruses to detect amount of phosphoruses of to-be-processed water that flows out of final sedimentation tank out of system, and anaerobic tank influent volume adjustment unit to adjust amount of bypass inflow to-be-processed water to anaerobic tank.    USE - A control apparatus of biological water treatment apparatus.    ADVANTAGE - The apparatus performs denitrification and phosphorus discharge efficiently, and ensures favorable water quality.    DETAILED DESCRIPTION - A control apparatus of biological water treatment apparatus comprises biologic reactor (2) which has primary sedimentation basin (1) and anaerobic tank (4), anaerobic tank (5), aerobic tank (6), final sedimentation tank (3), anaerobic tank influent volume control signal output unit to output signal which makes amount of bypass inflow to-be-processed water of to-be-processed water as predetermined value by which bypass inflow is carried out from system outside not via primary sedimentation basin to anaerobic tank according to output value of amount detection unit of outflow phosphoruses, amount detection unit of outflow phosphoruses to detect amount of phosphoruses of to-be-processed water that flows out of final sedimentation tank out of system, and anaerobic tank influent volume adjustment unit to adjust amount of bypass inflow to-be-processed water to anaerobic tank according to output value of anaerobic tank influent volume adjustment signal output unit. The to-be-processed water which flowed in from system outside flows in into primary sedimentation basin. The to-be-processed water which flowed in into primary sedimentation basin mixes with activated sludge which flows out of primary sedimentation basin, flows in into biologic reactor, and is stored in biologic reactor. The liquid mixture of to-be-processed water and activated sludge moves in order of anaerobic tank, anaerobic tank and aerobic tank. The to-be-processed water is processed with activated sludge in-between. The liquid mixture which flowed out of biologic reactor flows in into final sedimentation tank and separates into activated sludge and to-be-processed water after activated sludge treatment in final sedimentation tank. The to-be-processed water after activated sludge treatment applies to biological water treatment apparatus discharged out of system.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of control apparatus of biological water treatment apparatus. (Drawing includes non-English language text).    Primary sedimentation basin (1)    Biologic reactor (2)    Final sedimentation tank (3)    Anaerobic tank (4)    Anaerobic tank (5)    Aerobic tank (6)